Gtx 750 ti 2x or GTX 960 4gb

Hi,
I have a question. I have a decent powered computer with 16 gb ram. I’m trying to decide on a video card. My power supply is rated 850w.

The options I have is a GTX 960 4gb or 2x GTX 750. I don’t do fairly complex scenes. Which would give the must bang for buck.

Vivienne

What CPU do you have?
How much vRAM have those GTX 750 Ti? You remember that the vRAM available in Cycles is not the sum of both. You will have available a total vRAM equal to the card with the lowest vRAM.

The Video Ram on the 750 TIis 2 GB and the 960 4 Gb.

2GB vRAM is currently little to Cycles/CUDA.
I had asked about your CPU. If you have an i7 CPU with many threads, this may be faster than the two GPU options that you are showing.

  1. cpu: i7-2700
  2. memory: 16 gig ddr3
  3. os : ubuntu 12.04 but ubuntu 14.04 soon

I guess you would not have advantages over the CPU with neither of these GPU options. Also if you have an i7 2700k, your CPU is overclockable and can improve the times.
You try to get at least a GTX 970.

You can do tests with these two scenes in this thread (render times in message #1 and #4):
http://www.blenderartists.org/forum/showthread.php?375718-Cycles-GPU-CUDA-slow-with-some-materials

I wish. My budget puts me in those two GPU categories for now unless by some miracle the 970 was just into the 200/250 price range category.

If your scenes will not use SSS, hair, complex transparent/translucent materials with emission node plugged in Volume and volumetrics in general, then the GTX 960 4GB can be more than twice as fast as your CPU (not overclocked).
What were your CPU render time with the two scenes that I have shared in the thread above?

The first one was 59 seconds with the default settings and the second about 5 mins 3 seconds

Sorry, I forgot to say that in addition to choosing CPU under Device, you must choose the size of Tiles: x=32, y=32 under Performance. You should see 8 small tiles working simultaneously.
Anyway I think that you get a weird render time with the second scene. Did you use the scene from message #2 in the other thread, right?

Im not a computer to try it but seeing my render times. Comparably I would 2 to 3 times my CPU.

I previously had a 560 ti and there was a noticeable difference.

I think short term I can do one or two of thesewww.evga.com/Products/Product.aspx?pn=02G-P4-1955-KR until I can get a full 970.