Using GTX Titan as a secondary card without a display attached


I’ve recently built a new machine with the following specs:
GigaByte X79S-UP5-WIFI motherboard (BIOS F4w)
Intel 3930K core i7 CPU
32 GB Corsair Vengeance memory (4x8GB)
1 TB Seagate Barracuda harddisk
1 GTX Titan 6 GB DDR5
1 GT 640 2GB DDR3

OS: Open Suse 12.1

It seems that the system insist the display to be attached to the Titan card - even if I plug it in at the second PCIe x16 slot and place the GT 640 in the primary PCIe x16 slot. I want to use the GT 640 for display and the Titan for computing.

So far, even if I attach the display to the GT 640, the system starts up without picture, the monitor is just blank but I can hear the harddisk working so I assume it’s loading the OS. I’m mostly going to use the machine for compute and not graphics hence I want to avoid the watchdog on the Titan when running long computations.

Does anyone know if it is possible? Or am I doing something wrong?

Until I upgraded the BIOS (necessary to get the MB to support Titan) there was an option to select the PCI slot for the display adapter but after the upgrade that option is now gone…

I want to do the same with my GT520, too. It will be great if someone can help us.

On my system – MSI X79a-GD65 (8D) motherboard, interchanging the slots for the Titan / alternate video card did it. If both of you have no luck, try initiating a support request with your motherboard manufacturer and see if they are able to help with a BIOS mod, it’s worth a try.

My suggestion off the top of my head (may or may not work) is try an different display output on the alternate video card… e.g. if you’re trying HDMI, try using the DVI output to the monitor instead. That alone might be why the lower end card is not syncing a display and the BIOS defaults to the Titan.

Thanks vacaloca - I did try to switch the cards but I think that was before applying the BIOS patch for GTX Titan support. I will try switching them again this afternoon.

Btw. I used the VGA output on the GT640 (and the DVI-D to VGA converter on the Tital).

Update - it seems to have been the BIOS update for Titan that did the trick.

I swapped the cards (GT640 on primary PCIe x16 slot, Titan on secondary PCIe x16 slot) and the system now uses the GT640 for display :-)

Thanks vacaloca - I wasn’t completely off target but I never checked swapping slots after applying BIOS updates.

Cheers from a happy coder :-)

Hi rfosdal, do you have a dual boot system? I want to have a setup like yours but I want Ubuntu to use the lesser card for display and Windows to use Titan. If you have a dual boot system, can you give it a try to see how this works? Thanks


If I’m understanding correctly, you want Linux to drive display with lesser card and Windows to drive display with Titan? If so, I do not think this is possible without physically switching the video output cables before bootup. You might be able to accomplish this somehow using video switches perhaps, but I have no idea.

ymc - no I don’t use dual-boot. In fact I don’t have a single Windows machine (except for a virtual machine on my Macbook which is necessary for my daily work).
Physically switching the cards was what did the trick after upgrading the BIOS to support Titan.