Warning: Performance loss: number of rendering threads (XX) is greater than number of light cache passes (64); some threads will be idle.

[THExDUKE]

Hello everyone,

for a recent project we have had big rental hardware with dual 24core Xeon processors. And since we plan to update our own systems, that was a good opportunity to check out performance with Maya and VRay Next etc. Rest of the system was 256 GB Ram, Quaddro 4000 (maybe it was RTX but not sure). Anyway, I was first blown away by the rendertimes, but then realized, that there seems to be a thread limitation as I saw the title warning popping up.
Is this true? Do we have a limitation here? Would be interesting to know regarding processor selection etc. This seems to be an old warning, because I found threads from 2015 with this warning there already.

Thanks in advance

[dgruwier]

Did you see this thread?
https://forums.chaosgroup.com/forum/...ber-of-threads

[THExDUKE]

Did you see this thread?
https://forums.chaosgroup.com/forum/...ber-of-threads

Sorry, no I haven´t seen that. I was searching for the exact warning message though. So this issue seems only to be relevant for LC calculation, right? Rendering itself is no deal then and uses all available threads and cores? Doesn´t completely clarify that in your linked thread.

Thanks.

[dgruwier]

That's how I read it as well. It's the number of threads used for LC, not for final sampling. But you could use the task manager to check that every core is utilized while rendering if you want to be sure.

[THExDUKE]

CPU was, as far as I remember ( it was two weeks ago and we don´t have those machines anymore) on full throttle. I was just curious and actually a bit confused. To be honest I find it a bit strange that a solution is not to be able to use all usable threads for a calculation. I wonder if this is on a to-do-list for any upcoming update or this will be a permanent "solution".

[vlado]

This should be fixed in our latest updates when using the new hash map based light cache.

Best regards,
Vlado

[THExDUKE]

This should be fixed in our latest updates when using the new hash map based light cache.

Best regards,
Vlado

Thanks Vlado,

seems that I have missed an update? Im on V-Ray Next for Maya update 1 (v4.12.01.00001 fom May 8 2019) - Ill have to check that out.

[yolov]

Please do, we've included a number of other improvements. The new release is named Update 2, version is 4.30.00.
You can read more about it here: https://forums.chaosgroup.com/forum/...-now-available

[THExDUKE]

Please do, we've included a number of other improvements. The new release is named Update 2, version is 4.30.00.
You can read more about it here: https://forums.chaosgroup.com/forum/...-now-available

I have installed the latest version and will have a look into the new features and improvements. Performance wise it´ll take some time till I can verify, that the initially posted issue is no more, since I don´t have that power cpu right now. Thank you guys anyway. I really do appreciate your fast responses I like that.
Have a great day.

[JonasNöll]

Hi, after a CPU upgrade I am always getting a warning: "Performance loss: number of rendering threads ( 128 ) is greater than number of light cache passes ( 64 ); some threads will be idle"
(V-Ray 5 Update 1, 3ds Max 2020)

So is there anything that should be adjusted? I read that Vlado mentioned in this thread that this warning shouldn't come up anymore but it does for me.

Edit: Sorry, noticed this here is the Maya Forum