GTX 690 Video card in Mac

[Stefanita Manea]

Hi Todd,

Please tell me what model of Cubix do you use.
I also wander if 2xGTX690 will work, on the same old Mac 3.1 (I have one by myself just empowered with 32GB RAM and GTX660Ti)

Thank you.
Steff

[Todd Yonteck]

Cubix GPU-Xpander Desktop 4

Theoretically the the two GTX690s would work. The operating system and Davinci appear to see the GTX690 as two separate cards. However one of the four GPUs would not be active with OSX as it can only handle 3 GPUs. I would just use a GTX680 and save some cash, unless you are looking at moving these cards over to Windows or another operating system in the future. I am getting decent performance with one GTX 690. Drive speed is also important. Only problem is DSLR H264 encoded movies wont play back at full speed. Not sure if that is CPU issue or if I need more GPU power. Certainly not drive problem. I am playing back Red 5k files at 24fps with multiple nodes no problem.

[Stefanita Manea]

Hi,
Thank you for answering.
Yes, the GTX680 can be an optimal solution, I’ll think about it.
Did you do any benchmarking/experiments with two GPU’s in CUBIX?
I have doubts that will work similar with SLI. I mean, in fact there is only one PCX used, so the speed is limited to that one. Also, the processors have a limit of allocating PCX resources. The system sees 2 GPU’s but this is a mater of driver, I’m afraid. The main idea is to test with one then two identical GPU’s and to benchmark the results in order to see the real performance. Of course, I’m not asking you to do that, just thinking… Thanks again, Steff.

[Eric Fiegehen]

Hi Steff,

Keep in mind that PCIe works differently than other I/O transport technologies. Although all 4 Xpander slots share the same host PC / Mac Pro 16-channel slot, each of the Desktop 4 slots are receiving the full 80Gbps, 16-channel bandwidth to the host system’s bus. This is due to the way Cubix programs the timing sequences of the PCIe switch sets we use in our products.

Another way to put this is that when you perform benchmarks, each Xpander slot appears in the management utility as 16-channel PCIe receiving full bandwidth from the host system. If the theoretical 80Gbps maximum bandwidth were being used continually (without the application letting up on CUDA cores used and bandwidth maximized), then you would eventually see bus saturation occur over a period of time. However, Cubix has never experienced this condition running Resolve on OSX or Windows (I don’t believe Linux configurations have done this either)when connected at PCIe Gen2 16-channel speeds.

Please feel free to contact me or Cubix Technical Support for additional information on this or other related subjects.

Eric Fiegehen
Director, Visualization & GPU Compute Solutions
Cubix Corporation
ericc@cubix.com
https://www.cubix.com

[Damian Smith]

Hi Steff,
I am also about to buy a 690 and put it in a desktop expander 2.

However, the varying results above do worry me.

If you were in my situation, knowing the technology better than I, what would you recommend?

My current configuration without the CUBIX is a 5770 card for monitoring with a single quadro 4000 for resolve in my 12 core 2.66 MACpro.

This was absolutely fine in speed until I upgraded to resolve 9.03. Now it just lags on everything. Pro res Alexa plays at about 15fps. Its pretty shit. With three nodes it now drops to 5fps.

Previously, in resolve this same file would have taken 10 nodes to slow that much. Thanks Blackmagic. Awesome.

This is why I have ordered a cubix. Currently on the shelf I have a spare quadro 4000 incase the first fails.
I would see myself putting this in to the CUBIX, with the first one and then one or two more cards depending on which.

Compared to my quadro’s, I dont see the 690 as a expensive card. Its about what I paid for the quadro when it was first released.

So I guess what I am asking is – without reinventing the wheel, is the 690 the best option for a MAC CUBIX expansion – to compliment the 2 quardo’s or would I get better performance from something else?

Regards
Damian

[Seigea O’reilly]

What kind of speed is this setup getting? Any comparisons for your computer with other configurations? Or some sort of semi-standard Resolve benchmark.
Is it really worth the Cubix box and the 690’s?