Threading Issues

[Nejc Kilar]

Hey guys and gals,

So long story short, I'm running a 2696v3 (x2) and I'm experiencing some really weird threading issues when running IR. At first I thought this was limited to Corona for Cinema 4D but lately I'm finding the same issues affects 3ds Max as well. I don't remember having these problems in 3ds Max before so I'm kind of weirded out right now.

Here is the link to a screen recording of the issues -> https://www.dropbox.com/s/6sm8g9mcizxd97r/Stuttering.mov?dl=0

Synopsis: Viewport works smooth at 100fps. You turn on Interactive Rendering and you get a really stuttery viewport with FPS going from 100 to 5 in miliseconds + the UI gets hammered (even things like mouse clicks get delayed or just don't work if you press them too fast after another action). You turn off Interactive Rendering and everything gets back to being normal.

Corona for Cinema 4D is actually way worse than that. Fun stuff. Also worth mentioning is that when one drags the Windows UI (the actual windows) around when the IR is running, you even notice those guys are stuttering.

What I've been able to figure out is that its some sort of a threading issue. If I limit my CPU threads from 72 to 36 the performance gets better. If I limit it to 4 threads its super smooth, exactly as one would expect it to be.

I actually have a couple of other users experiencing similar issues on a 2670v1 (x2 - 32 threads total) and the TR 2990wx. And yes, I know Windows supposedly sucks with high thread counts but this makes Xeons / Epycs and HEDT in general unusable.

So I guess I'm wondering, anyone else experiencing something similar or know of any remedies?

edit: no ram or hdd issues btw :)

[Nejc Kilar]

No takers on this one, eh? :)

Here is an example of running my 2x 2696v3 with 3ds Max 2017 + Corona 1.4 (smooth performance) compared to 3ds Max 2020 + Corona 3.0 (barely usable in a simple scene).

https://www.dropbox.com/s/kmh3vkienmijdph/3dsmax2017and2020.mov?dl=0

C4D is way worse than the above. Oh and do note, this is recorded with 36 threads instead of 72. Using 72 threads makes 2020 + Corona 3.0 / C4D unusable for production work.

So right now I'm wondering whether it is possible that it has something to do with the AVX? I reckon Corona added AVX support after 1.4?

After further testing I came to a conclusion that 3ds Max 2017 works fine without any stuttering no matter the Corona version I am using. Contrary, 3ds Max 2019 & 2020 are a stutter fest.

Still I'd like to point out that the same stuttering happens in C4D, no matter what render engine is used which leads me to believe this is not a Corona related issue at all.

Any thoughts from anyone perhaps?

[Philip kelly]

Looks ok to me, are you expecting a bit too much maybe?

[Nejc Kilar]

I suppose I could be but what isn't recorded is that 3ds Max 2020 for example barely registers mouse clicks if you press them too quickly. You can imagine it is near impossible to navigate a simple scene that way. Either way, the performance seems quite different to me between the two versions.

Also, remember, this is on 36 threads. If I turn on HT it gets _way_ worse.

Actually, here is an example of C4D running with 72 threads -> https://www.dropbox.com/s/4az69a2ehta32kh/Threading%20Issues.flv?dl=0

edit:
And 3ds Max 2020 & 2017 (in that order) on 72 threads -> https://www.dropbox.com/s/fx1ol2yuyckffof/3dsmax2020and2017.mov?dl=0

[burnin]

khm windows... if you can, test performance with pro workstation or server versions which are designed for HPC
but either way... find your way of zen, otherwise everything, whole universe will always be too slow and glitchy ;)

[Nejc Kilar]

Thats something I'm thinking of doing yeah, thanks for suggesting! I'm first trying to figure out if there are any changes to how things work there - Last thing I need is another update to waste my time :)

I guess its not so much about being zen and smooth but trying to figure out how to buy CPUs in the future. Spending 8000$ is not a sure thing it once was. I've got scenes that work fine with 2017 but can barely be navigated with IR running in 2019+. Don't even want to get into C4D, 72 thread kills performance in anything bigger than a room with a couple of spheres. -_-