Overclocking the graphics card?

[Alex_M]

I was wondering if we gain extra speed in Vray RT if we overclock our graphics cards? From what I tested with Octane's benchmark scene, it doesn't look like overclocking increased my results which was a bit strange to me. What's the case with Vray RT? And if overclocking the GPU really doesn't speed up rendering, my question is why?

[savage309]

I was wondering if we gain extra speed in Vray RT if we overclock our graphics cards? From what I tested with Octane's benchmark scene, it doesn't look like overclocking increased my results which was a bit strange to me. What's the case with Vray RT? And if overclocking the GPU really doesn't speed up rendering, my question is why?

I haven't test if personally, but V-Ray RT GPU should run faster if the GPU gets overclocked. If you overclock with 10% for example, I don't expect it to be 10% faster, however. This happens because you have limited bandwidth to the memory, thread schedulers, cache and many more hardware that will not get bigger because of the overclock.

[3LP]

I have tried to overclock several times my GPU
sometimes it does work, sometimes it's not, with the same scene, same everything.
Really strange as evga precision shows that the clock is running faster but it just behaves as if it hasn't been OCed.

When that happens, a reboot usually fix it. first thing I do when rebooting is to overclock before opening any program, and it usually works after that.
Keep in mind that once you OC too much and you got a cuda error, the CG will put itself in safe mode and you're running at 10-15% of to maximum speed, again, reboot fix the issue.

For my test, if I OC of 10%, I get 10% of speed increase in RT.

Stan

[Alex_M]

Thanks, Stan. I'll try this out. I'm using Gigabyte GTX 980 with MSI Afterburner. After overclocking I'm going to restart my PC and see if the performance increases.

[3LP]

Just keep in mind your GPU revert to the default settings once your overclock.
That why most of the GPU OC progs enable them to lunch at start of the session so you keep OC on at all times.

But when it fails, it's good to have the default loading

Cheers

[Alan Iglesias]

Like Stan, I have overclocked my cards and gotten up to a 20+% rendering speed increase. Just be careful as you can easily get them going too fast and (at least) the driver crashes. When I need extra speed, I test them, bring them up until they crash, and then back off a few % until can get reasonably stable performance with a significant increase in speed.

-Alan

[Alex_M]

Thanks, guys. I've now done some testing and the most stable before Windows hangs is GPU core clock of 1530 Mhz. Unfortunately there seems to be a limit built in the GTX 980 for the GPU core voltage and I can't increase it with more than 87 mV otherwise I could probably increase the core to 1600 Mhz. The temperatures allow to do this (the GTX 980 is a very cool chip) but the voltage limit seems to stop the OC potential. Anyone else experienced this? And can this voltage limit be evaded?

[Raph4]

I remember old way for transforming GeForce into Quadro with RivaTuner + specific files
and yes, graphic card transformed work really really better with 3d software and it's generally better than original Quadro
https://3dstudiouk.wordpress.com/201...adro-soft-mod/

I don't know if RivaTuner still exist, and if support recent graphic card.

[Alex_M]

I now had the time to test Vray RT with and without GPU overclock. The strange thing is that performance doesn't seem to increase regardless if it's overclocked or not! I enabled "Statistics" and watched the KPaths/s and it was the same in both situations. Anyone can explain why this happens? What's more interesting is that Octane's benchmark, as Vray RT, doesn't benefit from overclocking too. Then I tested with Arion Benchmark (CUDA) and LuxMark (OpenCL) and both these renderers benefited from overclocking. Does that mean that Vray RT and Octane still don't fully support Maxwell GPUs like GTX 980?

[savage309]

All versions of V-Ray supports fully Fermi, Kepler and Maxwell (as well as every OpenCL device, if there is driver capable enough to compile and run the V-Ray code). Can you monitor the time a scene takes to render, rather than the KPaths/s ?

[3LP]

As I said in a earlier post, overclocking gou, fir some reasons, doesn't do it all the time.
Evga shows that the clock is higher, but it doesn't change anything when rendering.
Reboot and the first thing you do is OC, and try again.
Sometimes I had to do it multiple times.
But when it works, it works great, and at that point, i guess octane will be Work too.

Stan

[Alex_M]

I've set MSI Afterburner to apply the OC immediately after reboot but I still don't see improvement in speed. I do see improvement in Arion Benchmark (which is CUDA), in Unigine Heaven and in LuxMark (Open CL) but none in Vray RT and Octane. I'm using the latest drivers - 350.12 WHQL. Max version is 2016 and Vray is 3.10.03. Exact model of my card is Gigabyte N980WF3OC-4GD.

Blagovest, I will try and see how long it takes to render rather than the Kpaths/s as you suggested and will report back.
EDIT: No, render times are the same. I even did a reboot before each test. When Vray was set to finish at Max Noise 0.01, render time is 28 seconds, regardless of clock speed.

[3LP]

Could you try with evga precision?
I think it use the same tech as msi afterburn but we never know :-/
Weird!

[Alex_M]

I just tried with EVGA Precision and still nothing. The strange thing is that if I overclock my old GTX 460 I see improvement in speed of ~20% in Vray RT and Octane but no improvement when I overclock the GTX 980. Is my card defective? Can anyone with GTX 980 test if overclocking increase their speed in Vray RT or Octane?

Thanks!

[Paul Oblomov]

Show ur OC settings