How to make sure both GPU's are enabled. Tweet

[AeroBlau]

So, I have two GTX 970's installed on my comp and I decided to do few tests on how Octane & Blender work with only one GPU vs. Two GPU's so I would know the performance difference between using only one GPU and using both.
I have both OctaneRender Server 3.05.3 and Blender - OctaneRender edition 11.24 (2.78a) (x64) installed and they're seemingly working nice, but I noticed some strange things while doing the tests.

I did rendering tests with the same exact scene trying different settings both in Blender and nVidia Control panel but to my surprise they had no effect whatsoever on the performance. I enabled and disabled SLI and even dedicated PhysX both to CPU and the second GPU and there wasn't any difference between any of the settings I tried.
Then I decided to de-check the GPU's in Blender and to my surprise even that didn't have any effect on the performance and it rendered the picture the same as with the other settings I tried. How is that possible?

Did I miss something or am I doing something wrong? Is there a way I can really make sure that both GPU's are enabled?

Here are a couple of screenshots of the infobar ( which remained the same, no matter what I did) and rendering panel with both GPU's unchecked.





Oh, and I used PMC as the rendering method for all the time and I have the latest nVidia driver installed.

Please help

Thank you in advance.

[afecelis]

Hi Aeroblau,

Octane recommends not using the cards connected via SLI. Simply check/uncheck the cards you want to use via the software.


check Octane's answer #8 regarding SLI (Hardware and Software section) on the FAQ's:
https://home.otoy.com/render/octane-ren ... #collapse8

Also, From this post:
viewtopic.php?f=25&t=1781

You don't need to worry about SLI as Octane wont work with SLI enabled. Its just the way that CUDA works. Yes it will use multiple GPU's at the same time, just not with SLI enabled. The big question about which GPU's to get will depend on how much RAM you think you will need. the gtx480 has more and run a bit faster, but 2x gtx470's will run faster then 1 gtx480 if you don't need the extra 300+ megs of ram. I haven't run proper stats on this as I don't have a gtx480, but I do have 2x gtx470's. It is friggin fast!!! I'd recommend that you get a motherboard with an nVidia built on gpu to run you main display setup and leave the gtx470/480's strictly for rendering. This will greatly improve your general navigation and OS work. You will ove how fast Octane renders your work.

[AeroBlau]

Hi Aeroblau,

Octane recommends not using the cards connected via SLI. Simply check/uncheck the cards you want to use via the software.


check Octane's answer #8 regarding SLI (Hardware and Software section) on the FAQ's:
https://home.otoy.com/render/octane-ren ... #collapse8

Also, From this post:
viewtopic.php?f=25&t=1781

You don't need to worry about SLI as Octane wont work with SLI enabled. Its just the way that CUDA works. Yes it will use multiple GPU's at the same time, just not with SLI enabled. The big question about which GPU's to get will depend on how much RAM you think you will need. the gtx480 has more and run a bit faster, but 2x gtx470's will run faster then 1 gtx480 if you don't need the extra 300+ megs of ram. I haven't run proper stats on this as I don't have a gtx480, but I do have 2x gtx470's. It is friggin fast!!! I'd recommend that you get a motherboard with an nVidia built on gpu to run you main display setup and leave the gtx470/480's strictly for rendering. This will greatly improve your general navigation and OS work. You will ove how fast Octane renders your work.

Yes, I know all this, but the question was about why disabling or enabling SLI in nVidia control panel and checking or unchecking the GPU boxes in Blender do not affect the rendering speed at all. CPU-Z shows that both GPU's are working, but the rendering speed stays the same no matter how the settings are. If I have checked only one GPU and get a certain rendering speed from that single GPU, enabling both should double the rendering speed right? This does not happen and that's the problem I'm trying to find answer to.

[dktw]

yeah, actually I have same problem, two gpus 1070 and 1060, both visible in blender plugin but ony one is rendering, don't know why ?
in octane standalone everything works fine, both cards are loaded so i assume it has to be something in the blender plugin, any ideas ?
regards
Daniel