Weird vsync issue causing regular fps drops only in windows build

Hello,

I'm working on a project using Unity 2018.4.11f1 and I'm experiencing a strange fps issue when vsync is enabled in the windows build.
Roughly every second the fps drops off to 30fps for a few frames before going back up to 60. This only happens in the windows build. In the editor it runs at a solid 60 fps, and if I do a build with vsync off it runs around 200fps.

From my testing it seems like it could be related to my graphics card drivers throttling the gpu. It's almost like it easily hits the target frame rate, then throttles back to far so the frame rate drops and it throttles back up.

Here is what I'm seeing in the profiler:


My gpu is an amd rx580. I've tried updating and performing a clean driver install with no luck, but I've not noticed this problem in any other games. On other computers with nvidia cards the game runs fine.

Anyone out there seen anything similar to this before?

Cheers

 

Thanks for the reply.

We're not setting the maxQueuedFrames so I'm assuming it's the default 2.
Interestingly, if I disable vsync and set Application.targetFrameRate to 60 the game runs fine.

Here are the rest of the quality settings I'm testing with:

I'll try running some tests with older graphics drivers - maybe there's some weirdness going there.

 

Yeah, the monitor is plugged directly into the graphics card. Here's a comparison of GPU usage with vsync enabled, and vsync disabled with targetFrameRate set to 60:


In task manager the GPU usage is sitting around 50% in both cases, but looking at the readout from the radeon software it seems like the problem is related to the clock speed. With vsync enabled it jumps around between 300 to 1125MHz and with vsync disabled and the target frame rate set to 60 it sits at a consistent 1366MHz.