Seemingly random GPU slowdown causing huge FPS drops in editor and build

Hey all.

Recently i've noticed odd fps drops occurring in both the editor and build versions of my project.
They happen maybe once every 5 mins or so and last up to about 10 seconds. During which the game becomes completely unplayable.

My scene is pretty simple and does not change at all during play. I am using some post-processing affects on multiple cameras.

GPU Profile Capture before slowdown:


GPU Profile Capture during slowdown:


It looks like there's a proportional increase in the time taken for everything to be handled by the GPU and doesn't look like there's a single obvious culprit.

I've tried:
Upgrading Unity from 19.1.3 -> 19.3.1.
Enabling/Disabling Vsync.
Updating my GPU Drivers.
Enabling/Disabling post-processing in the scene. (possibly reduces frequency but doesn't fix).

Any pointers would be hugely appreciated. - been stuck on this for a couple of days...
Thanks.

 

The first thing I'd do is test this on another computer to verify it is not just something with your machine. It could be GPU thermal throttle for example.

 

Update on this:
Through creating a new blank scene and disabling assets one by one, i've narrowed down the issue to the post processing.
It seems doing any post processing at all is causing these slow downs...

 

Update 2:
Switched the the universal render pipeline and the issue appears to be fixed.