Interactive or Render with VFB opened on 9950x freeze system

[MircoTosti Studio]

Hi guys,

after several tests I found that both in C4D ver. 2024 and 2025, when rendering scenes with VFB open instead of PICTURE VIEWER this causes a system freeze or a slow motion style slowdown of both the mouse and the entire system. Instead if the VFB is closed and you let the scene go to PICTURE VIEWER this does not happen.

Workstation with win11, X870e Aorus Master, Ryzen 9950x, 192GB ddr5 5200.
Ver. Corona 13 latest (Daily Build Aug 28 2024 from Chaos Corona About window).

Any possible solution?

[Nejc Kilar]

Howdy! Thank you for opening up a thread :) Does this apply to Interactive rendering or final render or both maybe?

[MircoTosti Studio]

Hi Nejc,

permanent system freeze often happens to me with interactive, while the system freezes partially/temporarily when I render the final part. Also, in the final render I noticed that if I don't open the VFB window, this temporary freeze happens less often than when I have the VFB window open.
Processor works consistently well at 100% when I render without sudden drops or gaps.. and the ram never reaches full usage with 192GB.

Any ideas?

[Nejc Kilar]

Hm hm, the devs are working on fixing some of the threading issues with high core count CPUs and I'm wondering if that'll resolve some of the issues you're having. I'll update this topic once the build is ready.

[bnji]

Hi there, thank you for bringing this to our attention.
Yeah, I'm wondering if it's a HW-related issue. (as it looks like)
We'll need to wait until the dev team releases the fixes mentioned by @Nejc
Sorry for the inconvenience.

[MircoTosti Studio]

Hi guys, I tried to lower the number of cores/threads of the CPU dedicated to the corona render from the corona settings that works in sync with that of c4d but the result does not change.. always same problem encountered. Furthermore it seems that the cores/threads even if set for example to 50% (8/16 instead of 16/32) always work all.

[tatarka]

try to run test under stable corona 11 or 12

[MircoTosti Studio]

Hi Guys,
I tried to install the hotfix2 version of corona12 but during both interactive and fixed rendering the workstation seems more stable even if it tries to slow down the system every now and then. I noticed that this occurs mostly with ver12 when rendering ends and denoising begins. In any case, it's better than 13 but the same problem remains despite the workstation working at full capacity and without holes or CPU drops as sometimes happens with 13.

[Nejc Kilar]

Hm hm, that build I was mentioned earlier, it is ready and you can download it from here:
https://drive.google.com/drive/folders/1u3jdwa6h-in-DT-PcMEqTsvUkyZVjjPh

Would you mind giving it a try and reporting back if this in any way shape of form helps with your issue?

Thanks!

[MircoTosti Studio]

Hi,
I installed the latest build but the problem remains the same, if not worse. While before the freeze or slowdown was not immediate, now it is almost immediately.

[burnin]

Does it happen w/ VFB2 or Legacy or both?

Had previously noticed similar pattern and switched to Legacy VFB.
Latest v13 daily seems OK for time being.

[MircoTosti Studio]

It happens to me with both versions. As a check I did the same tests in 3dsmax and I don't have these problems.

[burnin]

Ok, another thing then, C4D specific.
Would you care to check, if it's same as this: "100% cpu in IPR usage in daily?"   

[MircoTosti Studio]

this thing happens to me too, as written in the post above C4D does not detect any changes to manually set cores/threads and always works at 100%

[TomG]

Note there was a bug, resolved internally, where negative numbers in the count of cores to be used in interactive was not working properly, and a few other scenarios where the value in the IR core count was not being respected. This fix will be in the final release, if not in an earlier RC.