GPU usage going down slowly while playing, causing stuttering

[CrazySpelz]

Hey guys,
I hope someone can help me with this.. having problems for a while now, but only with 2 specific games. (Weird thing is, these games dont have high requirements for PCs)

So first encounter with this problem was the Mass Effect 1 Remaster, while playing my GPU Usage dropped from 99-100% (perfect Framerates) to 20% and less. (10-15 FPS at worst case) and stayed low forever until I restarted the game. Found no solution back then, si I played the game and restarted every hour.
Now Im playing Bioshock Infinite Remastered, and I got the same annoying problem. Btw, I didnt have problems with Bioshock 1 and 2 Remastered.
I checked the temperatures, everything is okay, GPU goes to 80C° maximum. CPU Cram and Ram are fine too, and stay between 30 and 40% all the time, while playing. No changes here, its only the GPU.
Newer Games, that have much higher requirements for the PC work perfectly. For example AC: Valhalla or even Red Dead Redemption 2 on high settings. Played hours without any problems. Its only "older" games, that cause this problem. I tried to reinstall, reinstall graphic drivers completely new. Tried "stutter" fixes for Bioshock Infinite (setting VRAM higher in the Game Config file, deactivate VSync etc), nothing helps. I dont think its my Power supply either because then I would have much more problem in the heavy new games, that put all my PC to 100%m but they work perfect.

I play with an I7 7700k (not overclocked) and an RTX 2070 Super.

Please someone help me, because this is getting really really annoying. 

PS: Game works perfect about 1 hour on 99% GPU Usage. Then the drops begin, and after another hour Im at 50%. Then the game gets unplayable with audio glitches and stuttering. And like I said, no temperature problem.
PSU should be good too. Im not 199% sure what psu I have, but like I said, newer games like RDR2 work perfectly for 8 hours+. So it actually cant be a power problem.

[GuiltySpark_]

As soon as the change happens to the performance, i'd like to see what changes with with CPU AND GPU temp, usage and clockspeed. 

[CrazySpelz]

20 minutes ago, GuiltySpark_ said:

As soon as the change happens to the performance, i'd like to see what changes with with CPU AND GPU temp, usage and clockspeed. 

Temp stays the same from beginning to end. I will do another run now and have a look for the clock speed. Ill tell you more in about an hour! 

[JoHeJo06]

Maybe your cpu takes 1 hour to reach 80°c and that could be the throttling behavior?

[CrazySpelz]

3 minutes ago, JoHeJo06 said:

Maybe your cpu takes 1 hour to reach 80°c and that could be the throttling behavior?

No it doesnt. Temp and Clock stay the same all the time. And like I said, I played read dead redemption 2 all day long, with my GPU and CPU at 99% all the time. No problems at all, no heat problems no power problems etc. Its just those 2 specific games, that dont even need much ressources from my PC. 

[JoHeJo06]

What motherboard do you have?  Maybe your vrms can’t take it anymore

[CrazySpelz]

59 minutes ago, JoHeJo06 said:

What motherboard do you have?  Maybe your vrms can’t take it anymore

Acer Aspire GX-781. But if that would be the problem, why is everything else working perfectly and just this one game is lagging? 

[JoHeJo06]

Maybe this game needs more cpu Powah? I don’t play it but this ltt video explains Vrms. But for short: your vrms provide current to your cpu and if they get to hot, they will provide less power than your cpu desires. Or if they are to weak for a high power cpu.

 

Acer Aspire GX-781 is a prebuilt, not a motherboard.  Open your pc and look on the pcb of your motherboard, it is usually written somewhere around the pcie slot.