How does two gpus work?

Poul K. Sørensen asked:

I am current having a highend GPU installed in my server – and I am considering to install a cheap GPU to support the monitor.

Reason is that the server is using the highend GPU for OpenCL and i would like to reserve its resources for only calculations and not feeding the monitor. The motherboard has a PCI-E x8 (Gen2 X4 Link) slot.

Can I install a cheap GPU like ZOTAC GeForce GT 610 (512 MB), and use that as the main gpu for the monitor and then the highend gpu will be free for calculations.

I ask because i havent tried this before and i dont know how the OS (Windows Server) see the two cards and if i can select which GPU it should use for the monitor.

Alternative: If i dont plug in any monitor and control it by remote desktop from another pc, will it use gpu resources ?

My main problem is that if the calculations are long the OS stops the calculations because it think its stuck.

My answer:

You can throw in the GT 610 if you want, though in my experience it makes little difference.

Unless you do something crazy like install Desktop Experience on your server and turn on all the 3D Aero Glass effects, the load on the video card from displaying console video will be so minimal that you won’t even notice it.

If you’re really set on getting that last 0.5% of compute power out of the card, then by all means throw in the GT 610. Just remember to plug a monitor into it so Windows knows which card it should be using for the console display.

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