[SOLVED] Is "spiky" GPU usage sign of a CPU bottleneck?

[pegasuslatte]

Hello, recently got my hands on a used XFX RX 570.
I've tried benchmarking in some GPU intensive games, and I started to see this "spiky" GPU usage (0% to 52% or 90% and then straight down to 0%) both in MSI Afterburner and Radeon Software, sometimes it persists even when I'm casually browsing. This behavior, though, doesn't affect my in-game FPS. Funnily enough, this happened to in a less GPU intensive game i.e. Stardew Valley.

https://imgur.com/a/y8xt2zO

The less frequent spikes at the end was when I stopped playing.

I'm fully aware that my CPU (i3-2120, getting an upgrade next week) will bottleneck this GPU, and has seen this bottleneck in action (Witcher 2 High Settings on 1366 x 768 has an average of 58 FPS-ish), but am curious whether or not this "spiky" GPU usage is part of that bottleneck.

Any answer would be much appreciated, thanks!

 

[pegasuslatte]

Here's a Unigine Heaven benchmark score I got the other day using this benchmark setup:

https://imgur.com/tD4rcEQ

Score is a tad bit lower than the lower-end score from the same post (there are two RX 570 scores for the single GPU 1920x1080 benchmark) which is...kind of...expected? As the clock speed of my GPU is lower than the former (1264/1750 < 1280/1750).

Point is, my assumption is that the low average FPS in a low resolution is due to the CPU bottlenecking, hence the spiky GPU usage (GPU has to wait for the CPU etc.)

Any corrections + additions would be much appreciated!

 

[kaneelbagel]

yep, it's probably a cpu bottleneck, thats why the gpu usage goes up n down all the time, it doesn't get stuff to do from the cpu fast enough

 

[pegasuslatte]

Upgraded to an i5-3470 around 2 weeks ago, framerate is smoother and GPU usage, though still spiky, has some improvement.