Frame time spike once every minute in some unreal engine 3 games (Mass Effect Legendary Edition and Arkham Asylum, Arkham Origins)

[Tycho]

I have noticed that regardless of proton version and in game settings, there are a few games that have a huge frametime spike every minute. Just standing still for a minute in Arkham Asylum, Arkham Origins, or Mass Effect Legendary Edition (primarily in ME1, not the other two) will show a large frametime spike when basically nothing is going on. I have tried reinstalling those game too, and no improvement. One way to alleviate the visual stutter is to run the games at 30fps, but some Unreal Engine games have a separate problem where if the fps is capped below around 40 then you will experience much longer load times that normal (Fable Anniversary being an example, Fable Anniversary also displays the behavior, but the spike every minute is far less dramatic).

Not every game shows this behavior, for example I tested New Vegas and Fallout 4 and they didn’t have this issue. Granted, those aren’t UE3.
I also didn’t see this in Persona 3 Reload, which is also Unreal Engine, but UE4, if I recall right.

I am on Steam OS 3.6.20

Edit: New Vegas now has this issue in certain spots on the map. Additionally, if I manually set the GPU clock speed low enough (around 500mhz), then let a minute pass to trigger the spike, it will get stuck at around 10fps until i adjust the clock speed again. New Vegas seems almost random though. It sometimes triggers once a minute even when standing still, other times it doesn’t .

[Tycho]

An update:
All the recent (official and ge) protons seem to have this problem. However, I was able to get these games to not do that minutely frametime spike by switching to GE Proton 7-49, which seems to indicate that there was a regression somewhere with Unreal Engine 3 and Proton. Might further test to see where the cut off point in GE Proton is.
Edit: It seems to be something introduced around Proton 8 that causes this issue.

[Tycho]

Update:
Although official Proton 8, as well as GE from at least 8-25 on, shows this behavior, early versions of GE 8 (such as GE 8-4) do not. So it seems like it was something toward the middle of 8’s production that caused this regression in Unreal Engine 3 games.

[Tycho]

This issue continues to happen even with OS 3.6.21.

[Tycho]

Reformatting my OS and the problem persists straight out of the box on Proton 9 with no tweaks.