Dual Gtx 780 Mosaic with Dual 4k Asus PB287Q won't do 60Hz

maddeepee · December 16, 2014, 7:25am

Hello Guys,

i recently bought a new rig:

Two Geforce GTX 780
Two Asus PB287Q
Nvidia driver 346.22
Gentoo Kernel 3.14.14

connected a monitor to each card with Displayport, switched stream to DP1.2 on monitor Setup.
In short: i am unable to get BOTH monitors working in 60Hz, no matter what i do in config file.
Could anyone assist me with this? :(

I am able to run ONE monitor with ONE card at DP in 4k with 60Hz without any issues, though…

Is there any way to FORCE DP1.2 stream from the beginning?

cat /var/log/Xorg.0.log 
[   359.371] 
X.Org X Server 1.15.0
Release Date: 2013-12-27
[   359.371] X Protocol Version 11, Revision 0
[   359.371] Build Operating System: Linux 3.14.14-gentoo x86_64 Gentoo
[   359.371] Current Operating System: Linux MaDWorkStatioN 3.14.14-gentoo #18 SMP PREEMPT Tue Oct 7 00:26:30 CEST 2014 x86_64
[   359.371] Kernel command line: BOOT_IMAGE=/kernel-3.14.14-gentoo root=/dev/md2 ro resume=/dev/md1 rootfstype=ext4 video=uvesafb:1680x1050-32 quiet irqpoll
[   359.371] Build Date: 07 September 2014  05:22:10PM
[   359.371]  
[   359.371] Current version of pixman: 0.32.4
[   359.371]    Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
[   359.371] Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[   359.371] (==) Log file: "/var/log/Xorg.0.log", Time: Tue Dec 16 08:06:03 2014
[   359.371] (==) Using config file: "/etc/X11/xorg.conf"
[   359.371] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[   359.372] (==) ServerLayout "Layout0"
[   359.372] (**) |-->Screen "Screen0" (0)
[   359.372] (**) |   |-->Monitor "Monitor0"
[   359.372] (**) |   |-->Device "Device0"
[   359.372] (**) |-->Input Device "Keyboard0"
[   359.372] (**) |-->Input Device "Mouse0"
[   359.372] (**) Option "Xinerama" "0"
[   359.372] (==) Automatically adding devices
[   359.372] (==) Automatically enabling devices
[   359.372] (==) Automatically adding GPU devices
[   359.372] (==) FontPath set to:
        /usr/share/fonts/misc/,
        /usr/share/fonts/TTF/,
        /usr/share/fonts/OTF/,
        /usr/share/fonts/Type1/,
        /usr/share/fonts/100dpi/,
        /usr/share/fonts/75dpi/
[   359.372] (==) ModulePath set to "/usr/lib64/xorg/modules"
[   359.372] (WW) Hotplugging is on, devices using drivers 'kbd', 'mouse' or 'vmmouse' will be disabled.
[   359.372] (WW) Disabling Keyboard0                                                                                                                                                       
[   359.372] (WW) Disabling Mouse0                                                                                                                                                          
[   359.372] (II) Loader magic: 0x807c60                                                                                                                                                    
[   359.372] (II) Module ABI versions:                                                                                                                                                      
[   359.372]    X.Org ANSI C Emulation: 0.4                                                                                                                                                 
[   359.372]    X.Org Video Driver: 15.0                                                                                                                                                    
[   359.372]    X.Org XInput driver : 20.0                                                                                                                                                  
[   359.372]    X.Org Server Extension : 8.0                                                                                                                                                
[   359.378] (--) PCI:*(0:5:0:0) 10de:1004:10de:104b rev 161, Mem @ 0xb2000000/16777216, 0xa8000000/134217728, 0xb0000000/33554432, I/O @ 0x00009000/128, BIOS @ 0x????????/524288          
[   359.378] (--) PCI: (0:131:0:0) 10de:1004:10de:104b rev 161, Mem @ 0xfa000000/16777216, 0x381ff0000000/134217728, 0x381ff8000000/33554432, I/O @ 0x0000f000/128, BIOS @ 0x????????/524288
[   359.378] Initializing built-in extension Generic Event Extension                                                                                                                        
[   359.378] Initializing built-in extension SHAPE                                                                                                                                          
[   359.378] Initializing built-in extension MIT-SHM                                                                                                                                        
[   359.378] Initializing built-in extension XInputExtension                                                                                                                                
[   359.378] Initializing built-in extension XTEST                                                                                                                                          
[   359.378] Initializing built-in extension BIG-REQUESTS                                                                                                                                   
[   359.378] Initializing built-in extension SYNC                                                                                                                                           
[   359.378] Initializing built-in extension XKEYBOARD                                                                                                                                      
[   359.378] Initializing built-in extension XC-MISC                                                                                                                                        
[   359.378] Initializing built-in extension XINERAMA                                                                                                                                       
[   359.378] Initializing built-in extension XFIXES                                                                                                                                         
[   359.378] Initializing built-in extension RENDER                                                                                                                                         
[   359.378] Initializing built-in extension RANDR                                                                                                                                          
[   359.378] Initializing built-in extension COMPOSITE                                                                                                                                      
[   359.378] Initializing built-in extension DAMAGE                                                                                                                                         
[   359.378] Initializing built-in extension MIT-SCREEN-SAVER                                                                                                                               
[   359.378] Initializing built-in extension DOUBLE-BUFFER                                                                                                                                  
[   359.378] Initializing built-in extension RECORD                                                                                                                                         
[   359.378] Initializing built-in extension DPMS                                                                                                                                           
[   359.378] Initializing built-in extension Present                                                                                                                                        
[   359.378] Initializing built-in extension DRI3                                                                                                                                           
[   359.378] Initializing built-in extension X-Resource                                                                                                                                     
[   359.378] Initializing built-in extension XVideo                                                                                                                                         
[   359.378] Initializing built-in extension XVideo-MotionCompensation                                                                                                                      
[   359.378] Initializing built-in extension XFree86-VidModeExtension                                                                                                                       
[   359.378] Initializing built-in extension XFree86-DGA                                                                                                                                    
[   359.378] Initializing built-in extension XFree86-DRI                                                                                                                                    
[   359.378] Initializing built-in extension DRI2                                                                                                                                           
[   359.378] (II) LoadModule: "glx"                                                                                                                                                         
[   359.378] (II) Loading /usr/lib64/xorg/modules/extensions/libglx.so                                                                                                                      
[   359.393] (II) Module glx: vendor="NVIDIA Corporation"                                                                                                                                   
[   359.393]    compiled for 4.0.2, module version = 1.0.0                                                                                                                                  
[   359.393]    Module class: X.Org Server Extension                                                                                                                                        
[   359.393] (II) NVIDIA GLX Module  346.22  Tue Dec  2 10:20:26 PST 2014                                                                                                                   
[   359.393] Loading extension GLX                                                                                                                                                          
[   359.393] (II) LoadModule: "nvidia"                                                                                                                                                      
[   359.393] (II) Loading /usr/lib64/xorg/modules/drivers/nvidia_drv.so                                                                                                                     
[   359.393] (II) Module nvidia: vendor="NVIDIA Corporation"                                                                                                                                
[   359.393]    compiled for 4.0.2, module version = 1.0.0                                                                                                                                  
[   359.393]    Module class: X.Org Video Driver                                                                                                                                            
[   359.393] (II) NVIDIA dlloader X Driver  346.22  Tue Dec  2 09:58:48 PST 2014                                                                                                            
[   359.393] (II) NVIDIA Unified Driver for all Supported NVIDIA GPUs                                                                                                                       
[   359.394] (++) using VT number 7                                                                                                                                                         
                                                                                                                                                                                            
[   359.394] (II) Loading sub module "fb"                                                                                                                                                   
[   359.394] (II) LoadModule: "fb"                                                                                                                                                          
[   359.394] (II) Loading /usr/lib64/xorg/modules/libfb.so                                                                                                                                  
[   359.394] (II) Module fb: vendor="X.Org Foundation"                                                                                                                                      
[   359.394]    compiled for 1.15.0, module version = 1.0.0                                                                                                                                 
[   359.394]    ABI class: X.Org ANSI C Emulation, version 0.4                                                                                                                              
[   359.394] (II) Loading sub module "wfb"                                                                                                                                                  
[   359.394] (II) LoadModule: "wfb"                                                                                                                                                         
[   359.394] (II) Loading /usr/lib64/xorg/modules/libwfb.so                                                                                                                                 
[   359.394] (II) Module wfb: vendor="X.Org Foundation"                                                                                                                                     
[   359.394]    compiled for 1.15.0, module version = 1.0.0                                                                                                                                 
[   359.394]    ABI class: X.Org ANSI C Emulation, version 0.4                                                                                                                              
[   359.394] (II) Loading sub module "ramdac"                                                                                                                                               
[   359.394] (II) LoadModule: "ramdac"                                                                                                                                                      
[   359.394] (II) Module "ramdac" already built-in
[   359.395] (**) NVIDIA(0): Depth 24, (--) framebuffer bpp 32
[   359.395] (==) NVIDIA(0): RGB weight 888
[   359.395] (==) NVIDIA(0): Default visual is TrueColor
[   359.395] (==) NVIDIA(0): Using gamma correction (1.0, 1.0, 1.0)
[   359.395] (**) NVIDIA(0): Option "Stereo" "0"
[   359.395] (**) NVIDIA(0): Option "nvidiaXineramaInfoOrder" "DFP-4"
[   359.395] (**) NVIDIA(0): Option "SLI" "AFR"
[   359.395] (**) NVIDIA(0): Option "BaseMosaic" "On"
[   359.395] (**) NVIDIA(0): Stereo disabled by request
[   359.395] (**) NVIDIA(0): NVIDIA SLI alternate frame rendering selected.
[   359.395] (**) NVIDIA(0): Option "MetaModes" "GPU-77ec278d-3c36-9b8c-0fc4-c2d401d5c490.DP-1: nvidia-auto-select +0+0, GPU-e175e4c8-fab3-40ab-40fe-7517af41f893.DP-1: nvidia-auto-select +3840+0"
[   359.395] (**) NVIDIA(0): Enabling 2D acceleration
[   360.964] (II) NVIDIA(GPU-0): NVIDIA Base Mosaic enabled.
[   361.133] (II) NVIDIA(0): NVIDIA GPU GeForce GTX 780 (GK110) at PCI:5:0:0 (GPU-0)
[   361.133] (--) NVIDIA(0): Memory: 3145728 kBytes
[   361.133] (--) NVIDIA(0): VideoBIOS: 80.10.36.00.01
[   361.133] (II) NVIDIA(0): Detected PCI Express Link width: 16X
[   361.133] (II) NVIDIA(0): NVIDIA GPU GeForce GTX 780 (GK110) at PCI:131:0:0 (GPU-1)
[   361.133] (--) NVIDIA(0): Memory: 3145728 kBytes
[   361.133] (--) NVIDIA(0): VideoBIOS: 80.10.36.00.01
[   361.133] (II) NVIDIA(0): Detected PCI Express Link width: 16X
[   361.219] (--) NVIDIA(0): Valid display device(s) on GeForce GTX 780 at PCI:5:0:0
[   361.219] (--) NVIDIA(0):     CRT-0
[   361.219] (--) NVIDIA(0):     DFP-0
[   361.219] (--) NVIDIA(0):     DFP-1
[   361.219] (--) NVIDIA(0):     DFP-2
[   361.219] (--) NVIDIA(0):     DFP-3
[   361.219] (--) NVIDIA(0):     Ancor Communications Inc ASUS PB287Q (DFP-4) (boot, connected)
[   361.219] (--) NVIDIA(GPU-0): CRT-0: 400.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): DFP-0: Internal TMDS
[   361.219] (--) NVIDIA(GPU-0): DFP-0: 330.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): DFP-1: Internal TMDS
[   361.219] (--) NVIDIA(GPU-0): DFP-1: 165.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): DFP-2: Internal TMDS
[   361.219] (--) NVIDIA(GPU-0): DFP-2: 165.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): DFP-3: Internal TMDS
[   361.219] (--) NVIDIA(GPU-0): DFP-3: 330.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): Ancor Communications Inc ASUS PB287Q (DFP-4): Internal DisplayPort
[   361.219] (--) NVIDIA(GPU-0): Ancor Communications Inc ASUS PB287Q (DFP-4): 400.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): Valid display device(s) on GeForce GTX 780 at PCI:131:0:0
[   361.219] (--) NVIDIA(0):     CRT-0
[   361.219] (--) NVIDIA(0):     DFP-0
[   361.219] (--) NVIDIA(0):     DFP-1
[   361.219] (--) NVIDIA(0):     DFP-2
[   361.219] (--) NVIDIA(0):     DFP-3
[   361.219] (--) NVIDIA(0):     Ancor Communications Inc ASUS PB287Q (DFP-4) (boot, connected)
[   361.219] (--) NVIDIA(GPU-1): CRT-0: 400.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): DFP-0: Internal TMDS
[   361.219] (--) NVIDIA(GPU-1): DFP-0: 330.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): DFP-1: Internal TMDS
[   361.219] (--) NVIDIA(GPU-1): DFP-1: 165.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): DFP-2: Internal TMDS
[   361.219] (--) NVIDIA(GPU-1): DFP-2: 165.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): DFP-3: Internal TMDS
[   361.219] (--) NVIDIA(GPU-1): DFP-3: 330.0 MHz maximum pixel clock
[   361.219] (--) NVIDIA(0): Ancor Communications Inc ASUS PB287Q (DFP-4): Internal DisplayPort
[   361.219] (--) NVIDIA(GPU-1): Ancor Communications Inc ASUS PB287Q (DFP-4): 400.0 MHz maximum pixel clock
[   361.219] (**) NVIDIA(0): Using HorizSync/VertRefresh ranges from the EDID for display
[   361.219] (**) NVIDIA(0):     device Ancor Communications Inc ASUS PB287Q (DFP-4) (Using
[   361.219] (**) NVIDIA(0):     EDID frequencies has been enabled on all display
[   361.219] (**) NVIDIA(0):     devices.)
[   361.238] (**) NVIDIA(0): Using HorizSync/VertRefresh ranges from the EDID for display
[   361.238] (**) NVIDIA(0):     device Ancor Communications Inc ASUS PB287Q (DFP-4) (Using
[   361.238] (**) NVIDIA(0):     EDID frequencies has been enabled on all display
[   361.238] (**) NVIDIA(0):     devices.)
[   361.243] (II) NVIDIA(0): Validated MetaModes:
[   361.243] (II) NVIDIA(0):    
[   361.243] (II) NVIDIA(0):     "GPU-77ec278d-3c36-9b8c-0fc4-c2d401d5c490.DP-1:nvidia-auto-select+0+0,GPU-e175e4c8-fab3-40ab-40fe-7517af41f893.DP-1:nvidia-auto-select+3840+0"
[   361.243] (II) NVIDIA(0): Virtual screen size determined to be 7680 x 2160
[   361.246] (--) NVIDIA(0): DPI set to (157, 161); computed from "UseEdidDpi" X config
[   361.246] (--) NVIDIA(0):     option
[   361.246] (--) Depth 24 pixmap format is 32 bpp
[   361.246] (II) NVIDIA: Using 3072.00 MB of virtual memory for indirect memory
[   361.246] (II) NVIDIA:     access.
[   361.255] (II) NVIDIA(0): ACPI: failed to connect to the ACPI event daemon; the daemon
[   361.255] (II) NVIDIA(0):     may not be running or the "AcpidSocketPath" X
[   361.255] (II) NVIDIA(0):     configuration option may not be set correctly.  When the
[   361.255] (II) NVIDIA(0):     ACPI event daemon is available, the NVIDIA X driver will
[   361.255] (II) NVIDIA(0):     try to use it to receive ACPI event notifications.  For
[   361.255] (II) NVIDIA(0):     details, please see the "ConnectToAcpid" and
[   361.255] (II) NVIDIA(0):     "AcpidSocketPath" X configuration options in Appendix B: X
[   361.255] (II) NVIDIA(0):     Config Options in the README.
[   361.255] (II) NVIDIA(0): Setting mode "GPU-77ec278d-3c36-9b8c-0fc4-c2d401d5c490.DP-1:nvidia-auto-select+0+0,GPU-e175e4c8-fab3-40ab-40fe-7517af41f893.DP-1:nvidia-auto-select+3840+0"
[   361.911] Loading extension NV-GLX
[   361.998] (==) NVIDIA(0): Disabling shared memory pixmaps
[   361.998] (==) NVIDIA(0): Backing store enabled
[   361.998] (==) NVIDIA(0): Silken mouse enabled
[   361.998] (**) NVIDIA(0): DPMS enabled
[   361.998] Loading extension NV-CONTROL
[   361.999] Loading extension XINERAMA
[   361.999] (WW) NVIDIA(0): Option "Tripplebuffer" is not used
[   361.999] (II) Loading sub module "dri2"
[   361.999] (II) LoadModule: "dri2"
[   361.999] (II) Module "dri2" already built-in
[   361.999] (II) NVIDIA(0): [DRI2] Setup complete
[   361.999] (II) NVIDIA(0): [DRI2]   VDPAU driver: nvidia
[   361.999] (--) RandR disabled
[   362.006] (II) Initializing extension GLX
[   362.124] (II) config/udev: Adding input device Power Button (/dev/input/event7)
[   362.124] (**) Power Button: Applying InputClass "evdev keyboard catchall"
[   362.124] (II) LoadModule: "evdev"
[   362.124] (II) Loading /usr/lib64/xorg/modules/input/evdev_drv.so
[   362.124] (II) Module evdev: vendor="X.Org Foundation"
[   362.124]    compiled for 1.15.0, module version = 2.8.2
[   362.124]    Module class: X.Org XInput Driver
[   362.124]    ABI class: X.Org XInput driver, version 20.0
[   362.124] (II) Using input driver 'evdev' for 'Power Button'
[   362.124] (**) Power Button: always reports core events
[   362.124] (**) evdev: Power Button: Device: "/dev/input/event7"
[   362.125] (--) evdev: Power Button: Vendor 0 Product 0x1
[   362.125] (--) evdev: Power Button: Found keys
[   362.125] (II) evdev: Power Button: Configuring as keyboard
[   362.125] (**) Option "config_info" "udev:/sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input10/event7"
[   362.125] (II) XINPUT: Adding extended input device "Power Button" (type: KEYBOARD, id 6)
[   362.125] (**) Option "xkb_rules" "evdev"
[   362.125] (**) Option "xkb_model" "pc104"
[   362.125] (**) Option "xkb_layout" "us"
[   362.152] (II) config/udev: Adding input device Power Button (/dev/input/event6)
[   362.152] (**) Power Button: Applying InputClass "evdev keyboard catchall"
[   362.152] (II) Using input driver 'evdev' for 'Power Button'
[   362.152] (**) Power Button: always reports core events
[   362.153] (**) evdev: Power Button: Device: "/dev/input/event6"
[   362.153] (--) evdev: Power Button: Vendor 0 Product 0x1
[   362.153] (--) evdev: Power Button: Found keys
[   362.153] (II) evdev: Power Button: Configuring as keyboard
[   362.153] (**) Option "config_info" "udev:/sys/devices/LNXSYSTM:00/device:00/PNP0C0C:00/input/input9/event6"
[   362.153] (II) XINPUT: Adding extended input device "Power Button" (type: KEYBOARD, id 7)
[   362.153] (**) Option "xkb_rules" "evdev"
[   362.153] (**) Option "xkb_model" "pc104"
[   362.153] (**) Option "xkb_layout" "us"
[   362.153] (II) config/udev: Adding input device Logitech USB Keyboard (/dev/input/event1)
[   362.153] (**) Logitech USB Keyboard: Applying InputClass "evdev keyboard catchall"
[   362.153] (II) Using input driver 'evdev' for 'Logitech USB Keyboard'
[   362.153] (**) Logitech USB Keyboard: always reports core events
[   362.153] (**) evdev: Logitech USB Keyboard: Device: "/dev/input/event1"
[   362.153] (--) evdev: Logitech USB Keyboard: Vendor 0x46d Product 0xc326
[   362.153] (--) evdev: Logitech USB Keyboard: Found keys
[   362.153] (II) evdev: Logitech USB Keyboard: Configuring as keyboard
[   362.153] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5:1.0/0003:046D:C326.0001/input/input4/event1"
[   362.153] (II) XINPUT: Adding extended input device "Logitech USB Keyboard" (type: KEYBOARD, id 8)
[   362.153] (**) Option "xkb_rules" "evdev"
[   362.153] (**) Option "xkb_model" "pc104"
[   362.153] (**) Option "xkb_layout" "us"
[   362.154] (II) config/udev: Adding input device Logitech USB Keyboard (/dev/input/event2)
[   362.154] (**) Logitech USB Keyboard: Applying InputClass "evdev keyboard catchall"
[   362.154] (II) Using input driver 'evdev' for 'Logitech USB Keyboard'
[   362.154] (**) Logitech USB Keyboard: always reports core events
[   362.154] (**) evdev: Logitech USB Keyboard: Device: "/dev/input/event2"
[   362.154] (--) evdev: Logitech USB Keyboard: Vendor 0x46d Product 0xc326
[   362.154] (--) evdev: Logitech USB Keyboard: Found 1 mouse buttons
[   362.154] (--) evdev: Logitech USB Keyboard: Found scroll wheel(s)
[   362.154] (--) evdev: Logitech USB Keyboard: Found relative axes
[   362.154] (II) evdev: Logitech USB Keyboard: Forcing relative x/y axes to exist.
[   362.154] (--) evdev: Logitech USB Keyboard: Found absolute axes
[   362.154] (II) evdev: Logitech USB Keyboard: Forcing absolute x/y axes to exist.
[   362.154] (--) evdev: Logitech USB Keyboard: Found keys
[   362.154] (II) evdev: Logitech USB Keyboard: Configuring as mouse
[   362.154] (II) evdev: Logitech USB Keyboard: Configuring as keyboard
[   362.154] (II) evdev: Logitech USB Keyboard: Adding scrollwheel support
[   362.154] (**) evdev: Logitech USB Keyboard: YAxisMapping: buttons 4 and 5
[   362.154] (**) evdev: Logitech USB Keyboard: EmulateWheelButton: 4, EmulateWheelInertia: 10, EmulateWheelTimeout: 200
[   362.154] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5:1.1/0003:046D:C326.0002/input/input5/event2"
[   362.154] (II) XINPUT: Adding extended input device "Logitech USB Keyboard" (type: KEYBOARD, id 9)
[   362.154] (**) Option "xkb_rules" "evdev"
[   362.154] (**) Option "xkb_model" "pc104"
[   362.154] (**) Option "xkb_layout" "us"
[   362.154] (II) evdev: Logitech USB Keyboard: initialized for relative axes.
[   362.154] (WW) evdev: Logitech USB Keyboard: ignoring absolute axes.
[   362.155] (**) Logitech USB Keyboard: (accel) keeping acceleration scheme 1
[   362.155] (**) Logitech USB Keyboard: (accel) acceleration profile 0
[   362.155] (**) Logitech USB Keyboard: (accel) acceleration factor: 2.000
[   362.155] (**) Logitech USB Keyboard: (accel) acceleration threshold: 4
[   362.155] (II) config/udev: Adding input device Razer Razer Taipan (/dev/input/event3)
[   362.155] (**) Razer Razer Taipan: Applying InputClass "evdev pointer catchall"
[   362.155] (II) Using input driver 'evdev' for 'Razer Razer Taipan'
[   362.155] (**) Razer Razer Taipan: always reports core events
[   362.155] (**) evdev: Razer Razer Taipan: Device: "/dev/input/event3"
[   362.155] (--) evdev: Razer Razer Taipan: Vendor 0x1532 Product 0x34
[   362.155] (--) evdev: Razer Razer Taipan: Found 9 mouse buttons
[   362.155] (--) evdev: Razer Razer Taipan: Found scroll wheel(s)
[   362.155] (--) evdev: Razer Razer Taipan: Found relative axes
[   362.155] (--) evdev: Razer Razer Taipan: Found x and y relative axes
[   362.155] (II) evdev: Razer Razer Taipan: Configuring as mouse
[   362.155] (II) evdev: Razer Razer Taipan: Adding scrollwheel support
[   362.155] (**) evdev: Razer Razer Taipan: YAxisMapping: buttons 4 and 5
[   362.155] (**) evdev: Razer Razer Taipan: EmulateWheelButton: 4, EmulateWheelInertia: 10, EmulateWheelTimeout: 200
[   362.155] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.6/2-1.6:1.0/0003:1532:0034.0003/input/input6/event3"
[   362.155] (II) XINPUT: Adding extended input device "Razer Razer Taipan" (type: MOUSE, id 10)
[   362.155] (II) evdev: Razer Razer Taipan: initialized for relative axes.
[   362.155] (**) Razer Razer Taipan: (accel) keeping acceleration scheme 1
[   362.156] (**) Razer Razer Taipan: (accel) acceleration profile 0
[   362.156] (**) Razer Razer Taipan: (accel) acceleration factor: 2.000
[   362.156] (**) Razer Razer Taipan: (accel) acceleration threshold: 4
[   362.156] (II) config/udev: Adding input device Razer Razer Taipan (/dev/input/mouse0)
[   362.156] (II) No input driver specified, ignoring this device.
[   362.156] (II) This device may have been added with another device file.
[   362.156] (II) config/udev: Adding input device Razer Razer Taipan (/dev/input/event4)
[   362.156] (**) Razer Razer Taipan: Applying InputClass "evdev keyboard catchall"
[   362.156] (II) Using input driver 'evdev' for 'Razer Razer Taipan'
[   362.156] (**) Razer Razer Taipan: always reports core events
[   362.156] (**) evdev: Razer Razer Taipan: Device: "/dev/input/event4"
[   362.156] (II) evdev: Razer Razer Taipan: Using mtdev for this device
[   362.156] (--) evdev: Razer Razer Taipan: Vendor 0x1532 Product 0x34
[   362.156] (--) evdev: Razer Razer Taipan: Found 1 mouse buttons
[   362.156] (--) evdev: Razer Razer Taipan: Found scroll wheel(s)
[   362.156] (--) evdev: Razer Razer Taipan: Found relative axes
[   362.156] (II) evdev: Razer Razer Taipan: Forcing relative x/y axes to exist.
[   362.156] (--) evdev: Razer Razer Taipan: Found absolute axes
[   362.156] (--) evdev: Razer Razer Taipan: Found absolute multitouch axes
[   362.156] (--) evdev: Razer Razer Taipan: Found keys
[   362.156] (II) evdev: Razer Razer Taipan: Configuring as mouse
[   362.156] (II) evdev: Razer Razer Taipan: Configuring as keyboard
[   362.156] (II) evdev: Razer Razer Taipan: Adding scrollwheel support
[   362.156] (**) evdev: Razer Razer Taipan: YAxisMapping: buttons 4 and 5
[   362.157] (**) evdev: Razer Razer Taipan: EmulateWheelButton: 4, EmulateWheelInertia: 10, EmulateWheelTimeout: 200
[   362.157] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.6/2-1.6:1.1/0003:1532:0034.0004/input/input7/event4"
[   362.157] (II) XINPUT: Adding extended input device "Razer Razer Taipan" (type: KEYBOARD, id 11)
[   362.157] (**) Option "xkb_rules" "evdev"
[   362.157] (**) Option "xkb_model" "pc104"
[   362.157] (**) Option "xkb_layout" "us"
[   362.157] (II) evdev: Razer Razer Taipan: initialized for relative axes.
[   362.157] (WW) evdev: Razer Razer Taipan: ignoring absolute axes.
[   362.157] (**) Razer Razer Taipan: (accel) keeping acceleration scheme 1
[   362.157] (**) Razer Razer Taipan: (accel) acceleration profile 0
[   362.157] (**) Razer Razer Taipan: (accel) acceleration factor: 2.000
[   362.157] (**) Razer Razer Taipan: (accel) acceleration threshold: 4
[   362.157] (II) config/udev: Adding input device Razer Razer Taipan (/dev/input/event5)
[   362.157] (**) Razer Razer Taipan: Applying InputClass "evdev keyboard catchall"
[   362.157] (II) Using input driver 'evdev' for 'Razer Razer Taipan'
[   362.157] (**) Razer Razer Taipan: always reports core events
[   362.157] (**) evdev: Razer Razer Taipan: Device: "/dev/input/event5"
[   362.157] (--) evdev: Razer Razer Taipan: Vendor 0x1532 Product 0x34
[   362.157] (--) evdev: Razer Razer Taipan: Found keys
[   362.157] (II) evdev: Razer Razer Taipan: Configuring as keyboard
[   362.157] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.6/2-1.6:1.2/0003:1532:0034.0005/input/input8/event5"
[   362.157] (II) XINPUT: Adding extended input device "Razer Razer Taipan" (type: KEYBOARD, id 12)
[   362.157] (**) Option "xkb_rules" "evdev"
[   362.157] (**) Option "xkb_model" "pc104"
[   362.157] (**) Option "xkb_layout" "us"
[   362.158] (II) config/udev: Adding input device PC Speaker (/dev/input/event0)
[   362.158] (II) No input driver specified, ignoring this device.
[   362.158] (II) This device may have been added with another device file.
[   363.078] (**) NVIDIA(0): Using HorizSync/VertRefresh ranges from the EDID for display
[   363.078] (**) NVIDIA(0):     device Ancor Communications Inc ASUS PB287Q (DFP-4) (Using
[   363.078] (**) NVIDIA(0):     EDID frequencies has been enabled on all display
[   363.078] (**) NVIDIA(0):     devices.)
[   412.068] [mi] Increasing EQ size to 1024 to prevent dropped events.

cat /etc/X11/xorg.conf 
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 343.36  (buildmeister@swio-display-x86-rhel47-09)  Mon Dec  1 16:46:59 PST 2014

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    # generated from data in "/etc/conf.d/gpm"
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol"
    Option         "Device" "/dev/input/mice"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "Monitor0"
    VendorName     "Asus PB287Q"
    ModelName      "Ancor Communications Inc ASUS PB287Q"
    HorizSync       24.0 - 160.0
    VertRefresh     30.0 - 80.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 780"
    BusID          "PCI:5:0:0"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 780"
    BusID          "PCI:131:0:0"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "nvidiaXineramaInfoOrder" "DFP-4" 
    Option         "metamodes" "GPU-77ec278d-3c36-9b8c-0fc4-c2d401d5c490.DP-1: nvidia-auto-select +0+0, GPU-e175e4c8-fab3-40ab-40fe-7517af41f893.DP-1: nvidia-auto-select +3840+0"          
    Option         "Stereo" "0"
    Option         "SLI" "AFR"
    Option         "BaseMosaic" "On"
    Option         "Tripplebuffer" "On"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

xrandr 
Screen 0: minimum 8 x 8, current 7680 x 2160, maximum 16384 x 16384
GPU-0.DVI-I-0 disconnected primary (normal left inverted right x axis y axis)
GPU-0.DVI-I-1 disconnected (normal left inverted right x axis y axis)
GPU-0.HDMI-0 disconnected (normal left inverted right x axis y axis)
GPU-0.DP-0 disconnected (normal left inverted right x axis y axis)
GPU-0.DVI-D-0 disconnected (normal left inverted right x axis y axis)
GPU-0.DP-1 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 621mm x 341mm
   3840x2160      30.0*+
   2560x1600      60.0  
   2560x1440      60.0  
   1920x1080      60.0     59.9     50.0     60.0     50.0  
   1680x1050      60.0  
   1440x900       59.9  
   1280x1024      75.0     60.0  
   1280x960       60.0  
   1280x720       60.0     59.9     50.0  
   1152x864       75.0  
   1024x768       75.0     70.1     60.0  
   800x600        75.0     72.2     60.3     56.2  
   720x576        50.0  
   720x480        59.9  
   640x480        75.0     72.8     59.9     59.9  
   480x576        50.0  
   480x480        59.9  
GPU-1.DVI-I-0 disconnected (normal left inverted right x axis y axis)
GPU-1.DVI-I-1 disconnected (normal left inverted right x axis y axis)
GPU-1.HDMI-0 disconnected (normal left inverted right x axis y axis)
GPU-1.DP-0 disconnected (normal left inverted right x axis y axis)
GPU-1.DVI-D-0 disconnected (normal left inverted right x axis y axis)
GPU-1.DP-1 connected 3840x2160+3840+0 (normal left inverted right x axis y axis) 620mm x 340mm
   3840x2160      30.0*+
   2560x1600      60.0  
   2560x1440      60.0  
   1920x1080      60.0     59.9     50.0     60.0     50.0  
   1680x1050      60.0  
   1440x900       59.9  
   1280x1024      75.0     60.0  
   1280x960       60.0  
   1280x720       60.0     59.9     50.0  
   1152x864       75.0  
   1024x768       75.0     70.1     60.0  
   800x600        75.0     72.2     60.3     56.2  
   720x576        50.0  
   720x480        59.9  
   640x480        75.0     72.8     59.9     59.9  
   480x576        50.0  
   480x480        59.9

maddeepee · December 16, 2014, 1:33pm

Solved this by adding:

Option         "ModeValidation" "AllowNon60hzmodesDFPModes, NoEDIDDFPMaxSizeCheck, NoVertRefreshCheck, NoHorizSyncCheck, NoDFPNativeResolutionCheck, NoMaxSizeCheck, NoMaxPClkCheck, AllowNonEdidModes, NoEdidMaxPClkCheck"

in the Section “Screen” of xorg.com.

Nonetheless, SLI performs VERY bad under linux, no matter if Mosaic turned on or off. (SLI Mosaic doesn’t work with GTX).

For now i switched of SLI and i am just using this with base mosaic, having a dual 4k workspace @ both screens 60Hz (GTX 780@DP1.2)

To bad flash is crashing now all the time…

Cheers!

lakinwecker · November 8, 2015, 4:59pm

I am having a very similar issue. Except that I’m just trying to use a single monitor, but two cards in SLI mode at a 4k resolution with SLI turned on. I realize that SLI performs much worse than windows - but still it’s frustrating to not even be able to use it. SLI still performs better than a single card.

I believe I have the same issue as this poster, and I wanted to point out that his Option line doesn’t actually “Solve” the situation, rather it just hides the error.

The crux of the issue is that when you enable SLI in linux with even the latest drivers (355.11), the cards clock their pixel clock (Is this the same thing as the video clock?) down to 400.0 Mhz max. If you use single card, the maximum pixel clock is set to 960.0 Mhz.

Single Card:

[  1853.520] (**) NVIDIA(0): Enabling 2D acceleration
[  1853.866] (II) NVIDIA: Allocated GPU:0 (GPU-669d78ba-07f6-6da7-878b-bd3951ae8608) @
[  1853.866] (II) NVIDIA:     PCI:0000:01:00.0
[  1853.960] (--) NVIDIA(0): Valid display device(s) on GPU-0 at PCI:1:0:0
[  1853.960] (--) NVIDIA(0):     CRT-0
[  1853.960] (--) NVIDIA(0):     DFP-0
[  1853.960] (--) NVIDIA(0):     DFP-1
[  1853.960] (--) NVIDIA(0):     DFP-2
[  1853.960] (--) NVIDIA(0):     DFP-3
[  1853.960] (--) NVIDIA(0):     DFP-4 (boot)
[  1853.963] (--) NVIDIA(0): CRT-0: disconnected
[  1853.963] (--) NVIDIA(0): CRT-0 Name Aliases:
[  1853.963] (--) NVIDIA(0):   CRT
[  1853.963] (--) NVIDIA(0):   CRT-0
[  1853.963] (--) NVIDIA(0):   DPY-0
[  1853.963] (--) NVIDIA(0):   DVI-I-0
[  1853.963] (--) NVIDIA(0):   DVI-I-0
[  1853.963] (--) NVIDIA(0): CRT-0: 400.0 MHz maximum pixel clock
[  1853.963] (--) NVIDIA(0): 
[  1853.966] (--) NVIDIA(0): DFP-0: disconnected
[  1853.966] (--) NVIDIA(0): DFP-0: Internal TMDS
[  1853.966] (--) NVIDIA(0): DFP-0 Name Aliases:
[  1853.966] (--) NVIDIA(0):   DFP
[  1853.966] (--) NVIDIA(0):   DFP-0
[  1853.966] (--) NVIDIA(0):   DPY-1
[  1853.966] (--) NVIDIA(0):   DVI-I-1
[  1853.966] (--) NVIDIA(0):   DVI-I-1
[  1853.966] (--) NVIDIA(0): DFP-0: 330.0 MHz maximum pixel clock
[  1853.966] (--) NVIDIA(0): 
[  1853.966] (--) NVIDIA(0): DFP-1: disconnected
[  1853.966] (--) NVIDIA(0): DFP-1: Internal TMDS
[  1853.966] (--) NVIDIA(0): DFP-1 Name Aliases:
[  1853.966] (--) NVIDIA(0):   DFP
[  1853.966] (--) NVIDIA(0):   DFP-1
[  1853.966] (--) NVIDIA(0):   DPY-2
[  1853.966] (--) NVIDIA(0):   HDMI-0
[  1853.966] (--) NVIDIA(0):   HDMI-0
[  1853.966] (--) NVIDIA(0): DFP-1: 165.0 MHz maximum pixel clock
[  1853.966] (--) NVIDIA(0): 
[  1853.966] (--) NVIDIA(0): DFP-2: disconnected
[  1853.966] (--) NVIDIA(0): DFP-2: Internal TMDS
[  1853.966] (--) NVIDIA(0): DFP-2 Name Aliases:
[  1853.966] (--) NVIDIA(0):   DFP
[  1853.966] (--) NVIDIA(0):   DFP-2
[  1853.966] (--) NVIDIA(0):   DPY-3
[  1853.966] (--) NVIDIA(0):   DP-0
[  1853.966] (--) NVIDIA(0):   DP-0
[  1853.966] (--) NVIDIA(0): DFP-2: 165.0 MHz maximum pixel clock
[  1853.966] (--) NVIDIA(0): 
[  1853.966] (--) NVIDIA(0): DFP-3: disconnected
[  1853.966] (--) NVIDIA(0): DFP-3: Internal TMDS
[  1853.966] (--) NVIDIA(0): DFP-3 Name Aliases:
[  1853.966] (--) NVIDIA(0):   DFP
[  1853.966] (--) NVIDIA(0):   DFP-3
[  1853.966] (--) NVIDIA(0):   DPY-4
[  1853.966] (--) NVIDIA(0):   DVI-D-0
[  1853.966] (--) NVIDIA(0):   DVI-D-0
[  1853.966] (--) NVIDIA(0): DFP-3: 330.0 MHz maximum pixel clock
[  1853.966] (--) NVIDIA(0): 
[  1853.967] (--) NVIDIA(0): Samsung U28D590 (DFP-4): connected
[  1853.967] (--) NVIDIA(0): Samsung U28D590 (DFP-4): Internal DisplayPort
[  1853.967] (--) NVIDIA(0): Samsung U28D590 (DFP-4) Name Aliases:
[  1853.967] (--) NVIDIA(0):   DFP
[  1853.967] (--) NVIDIA(0):   DFP-4
[  1853.967] (--) NVIDIA(0):   DPY-5
[  1853.967] (--) NVIDIA(0):   DP-1
[  1853.967] (--) NVIDIA(0):   DPY-EDID-5093ddcd-a280-3a16-3af3-866adf090069
[  1853.967] (--) NVIDIA(0):   DP-1
[  1853.967] (--) NVIDIA(0): Samsung U28D590 (DFP-4): 960.0 MHz maximum pixel clock

SLI Mode:

[  1831.482] (**) NVIDIA(0): Enabling 2D acceleration
[  1832.475] (II) NVIDIA(GPU-0): NVIDIA SLI enabled.
[  1832.477] (II) NVIDIA: Allocated GPU:0 (GPU-669d78ba-07f6-6da7-878b-bd3951ae8608) @
[  1832.477] (II) NVIDIA:     PCI:0000:01:00.0
[  1832.477] (II) NVIDIA: Allocated GPU:1 (GPU-e8bab732-3915-8d0a-6c2f-a93185c7ac8f) @
[  1832.477] (II) NVIDIA:     PCI:0000:02:00.0
[  1832.624] (--) NVIDIA(0): Valid display device(s) on GPU-0 at PCI:1:0:0
[  1832.624] (--) NVIDIA(0):     CRT-0
[  1832.624] (--) NVIDIA(0):     DFP-0
[  1832.624] (--) NVIDIA(0):     DFP-1
[  1832.624] (--) NVIDIA(0):     DFP-2
[  1832.624] (--) NVIDIA(0):     DFP-3
[  1832.624] (--) NVIDIA(0):     DFP-4 (boot)
[  1832.627] (--) NVIDIA(0): CRT-0: disconnected
[  1832.627] (--) NVIDIA(0): CRT-0 Name Aliases:
[  1832.627] (--) NVIDIA(0):   CRT
[  1832.627] (--) NVIDIA(0):   CRT-0
[  1832.627] (--) NVIDIA(0):   DPY-0
[  1832.627] (--) NVIDIA(0):   DVI-I-0
[  1832.627] (--) NVIDIA(0):   DVI-I-0
[  1832.627] (--) NVIDIA(0): CRT-0: 400.0 MHz maximum pixel clock
[  1832.627] (--) NVIDIA(0): 
[  1832.629] (--) NVIDIA(0): DFP-0: disconnected
[  1832.629] (--) NVIDIA(0): DFP-0: Internal TMDS
[  1832.629] (--) NVIDIA(0): DFP-0 Name Aliases:
[  1832.629] (--) NVIDIA(0):   DFP
[  1832.629] (--) NVIDIA(0):   DFP-0
[  1832.629] (--) NVIDIA(0):   DPY-1
[  1832.629] (--) NVIDIA(0):   DVI-I-1
[  1832.629] (--) NVIDIA(0):   DVI-I-1
[  1832.629] (--) NVIDIA(0): DFP-0: 330.0 MHz maximum pixel clock
[  1832.629] (--) NVIDIA(0): 
[  1832.629] (--) NVIDIA(0): DFP-1: disconnected
[  1832.629] (--) NVIDIA(0): DFP-1: Internal TMDS
[  1832.629] (--) NVIDIA(0): DFP-1 Name Aliases:
[  1832.629] (--) NVIDIA(0):   DFP
[  1832.630] (--) NVIDIA(0):   DFP-1
[  1832.630] (--) NVIDIA(0):   DPY-2
[  1832.630] (--) NVIDIA(0):   HDMI-0
[  1832.630] (--) NVIDIA(0):   HDMI-0
[  1832.630] (--) NVIDIA(0): DFP-1: 165.0 MHz maximum pixel clock
[  1832.630] (--) NVIDIA(0): 
[  1832.630] (--) NVIDIA(0): DFP-2: disconnected
[  1832.630] (--) NVIDIA(0): DFP-2: Internal TMDS
[  1832.630] (--) NVIDIA(0): DFP-2 Name Aliases:
[  1832.630] (--) NVIDIA(0):   DFP
[  1832.630] (--) NVIDIA(0):   DFP-2
[  1832.630] (--) NVIDIA(0):   DPY-3
[  1832.630] (--) NVIDIA(0):   DP-0
[  1832.630] (--) NVIDIA(0):   DP-0
[  1832.630] (--) NVIDIA(0): DFP-2: 165.0 MHz maximum pixel clock
[  1832.630] (--) NVIDIA(0): 
[  1832.630] (--) NVIDIA(0): DFP-3: disconnected
[  1832.630] (--) NVIDIA(0): DFP-3: Internal TMDS
[  1832.630] (--) NVIDIA(0): DFP-3 Name Aliases:
[  1832.630] (--) NVIDIA(0):   DFP
[  1832.630] (--) NVIDIA(0):   DFP-3
[  1832.630] (--) NVIDIA(0):   DPY-4
[  1832.630] (--) NVIDIA(0):   DVI-D-0
[  1832.630] (--) NVIDIA(0):   DVI-D-0
[  1832.630] (--) NVIDIA(0): DFP-3: 330.0 MHz maximum pixel clock
[  1832.630] (--) NVIDIA(0): 
[  1832.631] (--) NVIDIA(0): Samsung U28D590 (DFP-4): connected
[  1832.631] (--) NVIDIA(0): Samsung U28D590 (DFP-4): Internal DisplayPort
[  1832.631] (--) NVIDIA(0): Samsung U28D590 (DFP-4) Name Aliases:
[  1832.631] (--) NVIDIA(0):   DFP
[  1832.631] (--) NVIDIA(0):   DFP-4
[  1832.631] (--) NVIDIA(0):   DPY-5
[  1832.631] (--) NVIDIA(0):   DP-1
[  1832.631] (--) NVIDIA(0):   DPY-EDID-5093ddcd-a280-3a16-3af3-866adf090069
[  1832.631] (--) NVIDIA(0):   DP-1
[  1832.631] (--) NVIDIA(0): Samsung U28D590 (DFP-4): 400.0 MHz maximum pixel clock

My monitor’s EDID supports 3840x2160@60hz, but only if your pixel clock can be set to 540Mhz.

[  1832.631] (--) NVIDIA(0): --- EDID for Samsung U28D590 (DP-1) ---
[  1832.631] (--) NVIDIA(0): EDID Version                 : 1.4
[  1832.631] (--) NVIDIA(0): Manufacturer                 : SAM
[  1832.631] (--) NVIDIA(0): Monitor Name                 : Samsung U28D590
[  1832.631] (--) NVIDIA(0): Product ID                   : 0x0b80
[  1832.631] (--) NVIDIA(0): 32-bit Serial Number         : 0x00000000
[  1832.631] (--) NVIDIA(0): Serial Number String         : 
[  1832.631] (--) NVIDIA(0): Manufacture Date             : 2013, week 52
[  1832.631] (--) NVIDIA(0): DPMS Capabilities            : Active Off
[  1832.631] (--) NVIDIA(0): Input Type                   : Digital
[  1832.631] (--) NVIDIA(0): Prefer first detailed timing : Yes
[  1832.631] (--) NVIDIA(0): Supports Continuous Frequency: No
[  1832.631] (--) NVIDIA(0): EDID 1.4 YCbCr 422 support   : Yes
[  1832.631] (--) NVIDIA(0): EDID 1.4 YCbCr 444 support   : Yes
[  1832.631] (--) NVIDIA(0): Maximum Image Size           : 610 mm x 350 mm
[  1832.631] (--) NVIDIA(0): Valid HSync Range            : 30.0 kHz - 134.0 kHz
[  1832.631] (--) NVIDIA(0): Valid VRefresh Range         : 56.0 Hz - 75.0 Hz
[  1832.631] (--) NVIDIA(0): EDID maximum pixel clock     : 540.0 MHz

Based on the above statement, the driver rejects this mode when SLI is turned on:

[  1832.635] (WW) NVIDIA(GPU-0):   Validating Mode "3840x2160_60":
[  1832.635] (WW) NVIDIA(GPU-0):     Mode Source: EDID
[  1832.635] (WW) NVIDIA(GPU-0):     3840 x 2160 @ 60 Hz
[  1832.635] (WW) NVIDIA(GPU-0):       Pixel Clock      : 533.25 MHz
[  1832.635] (WW) NVIDIA(GPU-0):       HRes, HSyncStart : 3840, 3888
[  1832.635] (WW) NVIDIA(GPU-0):       HSyncEnd, HTotal : 3920, 4000
[  1832.635] (WW) NVIDIA(GPU-0):       VRes, VSyncStart : 2160, 2163
[  1832.635] (WW) NVIDIA(GPU-0):       VSyncEnd, VTotal : 2168, 2222
[  1832.635] (WW) NVIDIA(GPU-0):       Sync Polarity    : +H -V 
[  1832.635] (WW) NVIDIA(GPU-0):     Mode is rejected: PixelClock (533.2 MHz) too high for
[  1832.635] (WW) NVIDIA(GPU-0):     Display Device (Max: 400.0 MHz).
[  1832.635] (WW) NVIDIA(GPU-0):     Mode "3840x2160_60" is invalid.

But it accepts this mode when SLI is turned off:

[  1853.983] (II) NVIDIA(GPU-0):   Validating Mode "3840x2160_60":
[  1853.983] (II) NVIDIA(GPU-0):     Mode Source: EDID
[  1853.983] (II) NVIDIA(GPU-0):     3840 x 2160 @ 60 Hz
[  1853.983] (II) NVIDIA(GPU-0):       Pixel Clock      : 533.25 MHz
[  1853.983] (II) NVIDIA(GPU-0):       HRes, HSyncStart : 3840, 3888
[  1853.983] (II) NVIDIA(GPU-0):       HSyncEnd, HTotal : 3920, 4000
[  1853.983] (II) NVIDIA(GPU-0):       VRes, VSyncStart : 2160, 2163
[  1853.983] (II) NVIDIA(GPU-0):       VSyncEnd, VTotal : 2168, 2222
[  1853.983] (II) NVIDIA(GPU-0):       Sync Polarity    : +H -V 
[  1853.983] (II) NVIDIA(GPU-0):     Viewport                 3840x2160+0+0
[  1853.983] (II) NVIDIA(GPU-0):       Horizontal Taps        0
[  1853.983] (II) NVIDIA(GPU-0):       Vertical Taps          0
[  1853.983] (II) NVIDIA(GPU-0):       Base SuperSample       x1
[  1853.983] (II) NVIDIA(GPU-0):       Base Depth             32
[  1853.983] (II) NVIDIA(GPU-0):       Distributed Rendering  1
[  1853.983] (II) NVIDIA(GPU-0):       Overlay Depth          32
[  1853.983] (II) NVIDIA(GPU-0):     Mode "3840x2160_60" is valid.

You can ask the driver to not validate the pixel clock of modes by including this option:

Option "ModeValidation" "NoMaxPClkCheck"

The driver then “pretends” to allow the mode to work, and even xrandr claims that you are running at 60Hz, but it is, in fact, in correct. You can test this by enabling an FPS counter in a game in steam, turning the graphics settings all the way down, except leaving the resolution at 4k and with vsync on, and you will only get 30fpx maximum.

maddeepee’s solution was the same disabling of mode validation of the pixel clock. What is unclear to me, is what exactly is the “Pixel Clock”. For reference, in windows, using HWInfo to report various attributes of the video card, it has a line item in it that is referred to as the “Video Clock” which is set to 540Mhz when driving the same monitor in an SLI configuration. So obviously, the hardware is capable of it, but the linux driver for some reason is artifically limiting the PixelClock Mhz to 400.

Apparently they fixed a similar issue in mosaic configurations in this driver: http://www.nvidia.com/Download/driverResults.aspx/84043/en-us

Fixed a bug that artificially limited the maximum pixel clock on displays in some SLI Mosaic configurations.

I think they probably need to apply a similar fix generally.