New CPU - 12900KF do not render all cores

[bocstudio]

Hi,
We just set up a new computer with the latest intel chip - 12900KF and tested the rendering performance.
Configuration :
CPU 12900KF - 18 cores - 24 threads
64GB RAM,
GPU RTX 3060 12GB

In the test of v-ray benchmark, everything works normally.
However, when I render in 3dsmax, V-ray only uses 8 Efficient (E) cores, detailed in the attached image.
I tried setting the environment variable VRAY_NUM_THREADS but it still doesn't solve the above problem.
Is it because v-ray has not adapted to the new generation of intel hardware and has to wait for the next updates?
Do you have any thoughts on how to handle the above problem? I can try them and feedback here.

Details you can see the pictures I attached below.

[hermit.crab]

You might wanna check if all the cores are active in the Windows settings (type msconfig in the Start menu > Boot > Advanced options > Number of processors). If that's not it, could you run a stress test on your CPU just to rule out hardware malfunctioning?

[oglu]

Im not sure if those e cores do render at all. Those new Hybrid CPUs are a strange thing.

[hermit.crab]

Yes, there might be some specifics about the core utilization of that specific model. Could you test if all cores are used in f.e. Arnold?

[^Lele^]

What your taskman is showing are the 16 threads from the 8 performance (i.e. the standard ones) cores working, while the 8 threads from the 8 efficient cores idle away.

[bocstudio]

What your taskman is showing are the 16 threads from the 8 performance (i.e. the standard ones) cores working, while the 8 threads from the 8 efficient cores idle away.

16 threads from the 8 performance are working for another task, not rendering. 8 threads from the 8 efficient cores are fullload not idle

[^Lele^]

Ah, you have timings active, i beg your pardon, i read it backwards.
I think we have one such chip at the office, I'll run some test and get back to you.

[^Lele^]

Rendering exactly the same asset as yours, under identical conditions, a single dome, under max 2022, seems to use all cores on our Alder Lake (ignore what the taskman says, it's an engineering sample).
Crucially, however, we have windows 11 on the workstation.

Can you share a bit more info on how it behaves?

[^Lele^]

Ah, yavor.rubenov found out a possible culprit.
If you use the "Balanced" power plan, and minimize Max while it renders (f.e. start+D to show the desktop), windows will move it to the E cores.
Below, the taskman when i minimised max while it was rendering.

[caypiranha]

admittedly, that was a long time ago. And there might be lots of reasons, why it is like this problem. I once had the problem, that 1 of my 4 cores failed to work. In this Case the task manager there also only showed 3 Cores and not all with one sleeping.
I replaced the CPU - the same thing. Then it was clear, reinstalling Windows should do the job - and it did so.

Using windows 10 or already 11? Maybe there is something different? (AMD had some issues there either on 11)

EDIT: uh! that seems to be solved. Sorry, overlapping this with the last from Lele...

[bocstudio]

Ah, yavor.rubenov found out a possible culprit.
If you use the "Balanced" power plan, and minimize Max while it renders (f.e. start+D to show the desktop), windows will move it to the E cores.
Below, the taskman when i minimised max while it was rendering.

It's just like normal scene we was rendering. When this happen, i think maybe the file have some problem so i test rendering in a new file with simple model from Cosmos and 01 Dome. Win 10 + 3dsmax 2022 - V-ray 5.2.
I'll try to test with Power plan and not minimize 3dsmax.

[goran_henic]

Hello!

Im having the same issue when using 3dsmax 2022 and latest Vray Next on a 12900k and Windows 10. While rendering with 3dsmax+vray both HWInfo and task manager show ONLY E-cores are at 100% while P-cores are fully idle or 10%-ish activity. It's either a 3dmax+vray bug or windows 10 doesnt know how to adjust the cores usage in that scenario. I'm gonna install windows 11 next week on a separate partition to see if the problem lies in windows.

When I run only max + arnold it uses every 12900k core at 100%. Likewise if im running Vray Benchmark 5 it will use all cores at 100% so this is just within 3dsmax issue.

Edit: forgot to mention minimizing/maximizing or changing energy profile stuff didnt make any difference.

[^Lele^]

Sneaky issue, thanks for chiming in.
Please do report in on your findings!

[matthieu_cordenier]

I had the same issue on my computer. Migrate to windows 11 solved the problem. Thx for all the advice.

[Alesh]

I started a similar thread but for Maya Vray. Same issue with this 12900K only using E cores when rendering in Vray, only in my case I'm using the machine with this CPU as a render node only, so I'm kicking off render from another machine.
For some reason Windows 10 treats Vray renderer as a background task so it only assigns it to E-cores while P-cores are completely unused sitting at 0% usage.
I don't want to upgrade to Windows 11 just for this. So far the workaround is to install this app called Process Lasso where you can assign Vray renderer process a high priority. Then all cores will be used used 100%. This app is installed as a service, so it's running every time you restart.
Would love to hear if there is an alternative solution that doesn't require installing the app or upgrading to Windows 11. Maybe this belongs on the Intel forum..