Double NVIDIA Quadro NVS 450

I have 2 “NVIDIA Quadro NVS 450” cards connected to 8 monitors. Only detects 2 monitors.
I installed
nvidia-340xx-dkms

xrandr -q
Screen 0: minimum 8 x 8, current 3840 x 1080, maximum 8192 x 8192
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 527mm x 296mm
   1920x1080     60.00*+  74.97    74.91    59.94    50.00    60.00    50.04  
   1680x1050     59.95  
   1440x900      59.89  
   1280x1024     75.02    60.02  
   1280x800      59.81  
   1280x720      60.00    59.94    50.00  
   1152x864      75.00  
   1024x768      75.03    70.07    60.00  
   800x600       75.00    60.32    56.25  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    59.94    59.93  
DP-3 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 527mm x 296mm
   1920x1080     60.00*+  74.97    74.91    59.94    50.00    60.00    50.04  
   1680x1050     59.95  
   1440x900      59.89  
   1280x1024     75.02    60.02  
   1280x800      59.81  
   1280x720      60.00    59.94    50.00  
   1152x864      75.00  
   1024x768      75.03    70.07    60.00  
   800x600       75.00    60.32    56.25  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    59.94    59.93 

lspci -k | grep -A 2 -E "(VGA|3D)"
05:00.0 3D controller: NVIDIA Corporation G98 [Quadro NVS 450] (rev a1)
	Subsystem: NVIDIA Corporation Device 0619
	Kernel driver in use: nvidia
--
06:00.0 VGA compatible controller: NVIDIA Corporation G98 [Quadro NVS 450] (rev a1)
	Subsystem: NVIDIA Corporation Device 0619
	Kernel driver in use: nvidia
--
09:00.0 3D controller: NVIDIA Corporation G98 [Quadro NVS 450] (rev a1)
	Subsystem: NVIDIA Corporation Device 0619
	Kernel driver in use: nvidia
--
0a:00.0 VGA compatible controller: NVIDIA Corporation G98 [Quadro NVS 450] (rev a1)
	Subsystem: NVIDIA Corporation Device 0619
	Kernel driver in use: nvidia

My Xorg.0.log → https://pastebin.com/rF1vRvXC
My dmesg → https://pastebin.com/H0PmX6zy

I am looking for an answer, why drivers detect only 2 monitors?

OS: Arch Linux, GUI: KDE

I replaced it with 4 x NVIDIA NVS 310 cards and it works