Variable according VGA performance?

[AndresAhumada]

I have a question that came out of a performance test with V-ray for 3d max per CPU.
In these test it shows that performance varies depending on the video card that is installed on your computer.
This test is to show that even a CPU processing, likewise works the GPU (in some proportion to).
It's like that at some stage in the collection or processing infromacion the same GPU intervenes. Although the engine is working on the CPU.
What I want is to know technically if this is real or due to other factors, such as the PCI bus or the relationship between the bus and reading ram.
I hope I can clarify my doubts.

Cheers

" This test was created and designed by https://www.facebook.com/romero.marco.a?fref=ts "

Test:











After participating in a test of rendering in Vray, I wanted to publicly share the results, as there is still the misconception that Vray rendering engine (standard) using only the CPU.

The rendering process involves calculating both the processor (CPU) and the graphics card (GPU), and the amount and type of cores are responsible for executing the calculation process data sent by the GPU, which in turn depends on the number of cores and dememoria type you use. The higher GPU has the largest capacity is the volume of data they send and manage the CPU, which in turn requires RAM depending on the speed and quantity run the calculation.

Facebook group "We talked V-Ray":
https://www.facebook.com/groups/habl...7479046452252/

Test scene:
https://mega.nz/#!9UcAHD7B!tJQhvmfUy...iJ9CxAmaC8TT2M

With this test it was found "and is confirmed" that the type of GPU influences in Vray render time, and that the performance of the GTX 690 (3072 Kepler CUDA Cores - 300W) was higher ligeramnete (by 3.2s) to the GTX 980TI (2816 CUDA Cores MAXWELL - 250W) despite their differences in electrical efficiency; for a third place for the GTX 980 (2048 CUDA Cores MAXWELL - 165W).

1st Place - GTX 690 (4GB - 3072 Kepler CUDA Cores - 300W):
http://www.geforce.com/hardware/desk...specifications

2nd Place - GTX 980 Ti specs (6GB - MAXWELL 2816 CUDA Cores - 250W):
http://www.geforce.com/hardware/desk...specifications

3rd Place - GTX 980 specs (4GB - MAXWELL 2048 CUDA Cores - 165W):
http://www.geforce.com/hardware/desk...specifications

Hardware: http://goo.gl/WqiqBp
Software: Advanced V-Ray for 3ds Max 2014 20.03.03 x64
CPU-Z: http://www.cpuid.com/softwares/cpu-z.html
GPU-Z: https://www.techpowerup.com/gpuz/

October 25, 2015

[3LP]

That's really weird and I wouldn't expect that.
We have nodes without GPU at all and they render fine. I think the answer has to come from something other than the GPU.
Don't know what though

Stan

[AndresAhumada]

Vlado be able to answer this big question.

[vlado]

The regular V-Ray renderer does not use GPU in anyway at all whatsoever. So I have no idea what those guys tested or how they came to that conclusion. The only thing that might come to mind is updating the VFB while rendering, but it would be extremely weird if any GPU is burdened by that.

Best regards,
Vlado

[AndresAhumada]

Hi Vlado

Thank you for your prompt response.

This guy makes testing and being exposed as a reality and convinced that vray is affected by the GPU.

This is exposing him to "speak Vray", which creates confusion and skepticism about it.

I'll leave the link of facebook where proposed this idea.

I hope you can clarify for new and future users do not become wrong idea of the case.


https://www.facebook.com/romero.marc...to_album_reply

[vlado]

Sorry, I don't have a Facebook account.

Best regards,
Vlado

[AndresAhumada]

I do understand...

There are some technical explanation to answer this user? something to leave him alone and can understand the operation of V-ray.

Because the claims that these tests show that if you use the GPU Vray anque this only works with the CPU.


Thanks for all Vlado.

[vlado]

Well you can give a link to this thread and the discussion can continue here?

Best regards,
Vlado

[Neilg]

in one there's a 0.7% difference, in the other is 2.1% difference.

If you render the same scene each day you'll probably see something similar without changing the video card. Our identical farm machines vary in render time by up to 5% rendering the same scene and the same frame - and the machines which do it quicker and slower changes every time.

[AndresAhumada]

The user you are doing these tests has not advanced access to 3Dmax forum. Any possibility of providing access?

so we have the info first hand.


http://forums.chaosgroup.com/member.php?225050-maromero

[vlado]

Well, there's the public forum, anyone can post there, so maybe start a new thread there?

Best regards,
Vlado

[AndresAhumada]

Oka .... no problem.

[auke]

As Neilg states the differences are very small and could be the result of normal variations between identical renders. Try rendering the same image on the same system 10 times and compare the render times, they will usually be slightly different. If this test would have a bigger sample size, for example 100 runs on gpu1, 100 runs on gpu2 and so on and you would compare the average times for each system they would likely be practically identical. Any remaining difference (I'd seriously doubt there would be any) could be related to inefficient drivers/programs running in the background.

[Richard7666]

in one there's a 0.7% difference, in the other is 2.1% difference.

If you render the same scene each day you'll probably see something similar without changing the video card. Our identical farm machines vary in render time by up to 5% rendering the same scene and the same frame - and the machines which do it quicker and slower changes every time.

Could be caused by operating system overhead I would imagine.