Slower CUDA performance with the latest nVidia drivers 353.62

[Zakkorn]

I don't if this happened to me only but I noticed a serious drop in performance after installing the latest drivers.
In the Benchmark scene of RT I went from 1840 KPaths/s to around 1190 KPaths/s.

In one of my scenes I rendered the same image with a limit of 1min.
The image rendered under the latest driv. (353.62) had a little more noise.
Thus slower render.

Did anyone else notice something similar?

PS I did this on a TitanX

[Donfarese]

hmm, I have a TitanX also but haven't downloaded the newest driver yet, guess I'm glad I haven't. Would be good to get some info on this.

[Zakkorn]

I found out this issue with win 8.1
So I could reinstall the previous drivers and remove the issue.

But I upgrade to Win 10 and now these are the only official drivers, so I have to wait for new ones. :P

[savage309]

I don't if this happened to me only but I noticed a serious drop in performance after installing the latest drivers.
In the Benchmark scene of RT I went from 1840 KPaths/s to around 1190 KPaths/s.

In one of my scenes I rendered the same image with a limit of 1min.
The image rendered under the latest driv. (353.62) had a little more noise.
Thus slower render.

Did anyone else notice something similar?

PS I did this on a TitanX

Which V-Ray version is that on what GPU are you using ?

KPaths is a number that can fluctuate during the render process - for example, when rays are traced in easier to render parts of the image like environment is one thing and when the rays are bouncing between objects is another.
The proper way to do a test is to set max paths per pixel and see how long it takes.

Using V-Ray 3.20.03 and Titan X, on my machine the benchmark 2 scene goes for roughly the same time.

[3LP]

I did upgraded my drivers also to the latest and had issues till Vray's support told me that the best drivers yet where the 350.12
So I rolled back and I didn't had major issues since.

Sorry to hear you're stuck with win 10 now :-/

Stan

[savage309]

I did upgraded my drivers also to the latest and had issues till Vray's support told me that the best drivers yet where the 350.12
So I rolled back and I didn't had major issues since.

Sorry to hear you're stuck with win 10 now :-/

Stan

V-Ray for Max 3.20.02 and 3.20.03 are working fine with all drivers. Same goes for 3.10.01 for Maya.

[Zakkorn]

Which V-Ray version is that on what GPU are you using?

I am using 3.20.02

I know that the KPaths is a number that can fluctuate during the render process.
In that Benchmark scene in the previous drivers the Kpaths after a while they stabilized at around 1800
But with the latest (353.62) at that particular stage they stabilized at around 1100.

And to give you a better idea of the issue (mine issue or every pc with the latest drivers?)
With the previous drivers I had 1:43 result
With the 353.62 I have a 2:49 result

Its a Huge difference

Thats why I am asking if anyone tested the latest drivers to check if this issue appears to his machine as well.

[Zakkorn]

OK I think the issue is gone after I put the 3.20.03 Vray

Strange though, as this had nothing to do with vray and I am pretty sure of it.

I am saying this because yesterday I had my Windows 8.1 Pro on my PC.
I put the 353.62 drivers and then I noticed this fall in performance under CUDA in Vray RT.
I revert back to the previous drivers and Vray RT regained its performance.
This clearly shows that is a nvidia driver issue somehow.

Later that day I upgrade my PC to Windows 10.
With Windows 10 the 353.62 drivers are installed by default as these are the official Win10 drivers.
Then I checked Vray RT and the slow performance returned (as it should as it goes with the 353.62 drivers... logically)

Yesterday as a coincidence (thankfully) Chaos released a new version of Vray.
Today I thought, lets try it, who knows.

And Baaam! the issue disappeared!

So I am still trying to understand what was causing the issue

[savage309]

What is your GPU ?
Is V-Ray 3.20.03 equally fast with the new and the old driver ?
Can you check the render speed of 3.20.02 vs 3.20.03 on your machine ?
Thanks,
Blago.

[Zakkorn]

My GPU as I said in the 1st post is a Titan X
3.20.02 1:43 (before the issue)
3.20.03 1:31

Thus the Vray RT is a little faster. Thats a good thing

[savage309]

My GPU as I said in the 1st post is a Titan X
3.20.02 1:43 (before the issue)
3.20.03 1:31

Thus the Vray RT is a little faster. Thats a good thing

Sorry, I have missed that. Thanks for the tests!
Glad that everything works as expected now.

[Zakkorn]

I really hope so.
Thanks for your effort of bringing better and better stuff.

[savage309]

I really hope so.
Thanks for your effort of bringing better and better stuff.

We have reproduced the issue. It is very strange that the 353.62 makes older V-Ray 3 versions slower. At least we have 3.20.03 for Max and 3.10.01 for Maya running fine.
We will report that to nVidia to see if they can fix it.
Thanks a lot,
Blago.

[Zakkorn]

No problem. Glad that I help on something -
And at least I learned that wasn't only on my PC.

Now that I began "playing" with RT I will found many strange things for sure :P

[savage309]

No problem. Glad that I help on something -
And at least I learned that wasn't only on my PC.

Now that I began "playing" with RT I will found many strange things for sure :P

You may find this useful http://docs.chaosgroup.com/display/V...rted+Features#