Hey guys, I’m looking at buying a Nvidia GPU for rendering in cycles, but I don’t want my current GPU to go to waste. My current GPU is a AMD R9 270X. I was wondering if I could use the GPU I have for my display and use the new card for Rendering. If so would that even give any benefit or am I better off just using the one card?
Thanks, Malcolm
Yes, you can have your 270X for display and another Nvidia card for render with Cycles. I can confirm that because I have a 270X and a GTX 570 and I just confirmed it myself.
Your motherboard must have two PCI-e slots, if they both work at x16 speed the result will be better - this feature is only avaliable in the top class of motherboards.
On my setup the GTX is on a PCI-e slot that is working at x4 speed, that means the card isn’t able to work with its full speed. Even so, the GTX completed the BMW benckmark in ~3min while my octacore CPU used ~9minutes.
Hi, I would just like to add, the PCIe speed does not influence render time only loading time.
Even PCIe x4 can handle GB per seconds.
@PrinceYann, could you try my benchmark file to compare with other GTX 570?
http://www.blenderartists.org/forum/showthread.php?359492-The-new-Cycles-GPU-2-73-Benchmark
Cheers, mib
Nvidia :evilgrin: 
Nicely said.
The result:
“Windows 8.1 - Blender 2.73
GTX 570 1280MB @ PCIe x4
200 x 240 - time 13:06.32
256 x 256 - time 12:46:82”
I put the results of the benchmark on that thread too.