Single frame spikes even in an empty project

Godot version:
3.1.1, 3.2b2

OS/device including version:
Windows 10 Pro 1909 x64

Issue description:
Every ~10 seconds i get a one-frame spike followed by 1-3 really short frames. At first i thought it was my fault, but problem persists even in an empty project.

Exported project exhibits same behavior.

My specs are i5 7300, 16gb DDR4, GTX 1050

Profiler screenshots:

Frame before the spike:

Spike:

Frame after the spike:

Steps to reproduce:

1. Attach a script with empty "_process" method anywhere in the scene, so that Editor may pause the scene (only for a profiler screenshot)
2. Run project and wait for ~10 sec

EDIT:
So, in trying to narrow down the issue(at least as far as my abilities go), i tested this on some other machines

i7 - 9750H / 16 Gb DDR4 / RTX-2060 w/ Windows 10 - same thing,
i3 - 3240 / 4 Gb RAM (didn't check at the time, i believe DDR3) / GeForce 8600GT w/ Windows 8.1 - same thing

I tried to check the first machine (i5 7300, 16gb DDR4, GTX 1050) with Manjaro 18.1.5 and didn't notice any of similar problems (although i couldn't get Vsync to work). Project, exported on Manjaro to Windows exhibits same behavior

3.2 rc4 didn't help.

EDIT 2: The Editing
I decided to try Vulkan branch just to see if something different happens.
Spikes aren't there, but i noticed really strange things happen with everything that is normalized for time (with delta), i haven't noticed this before because of short lag, but in Vulkan that short lag isn't there, and after some investigating, i found that sometimes delta is negative(with same frequency as spikes in stable version). Going back to 3.2, negative delta does happen at the same time as spikes, but not everytime.

So i guess, question is, could VSync issues and negative delta be related?

So, pull request #33414 fixes it in windowed mode, but in fullscreen it still happens, and sometimes its only short frame and visible stutter (without the spike)

[FeralBytes]

@SigMA0x How many FPS are you running? Is it possibly related to heat, or for that matter you are on Windows, are there other processes that are causing the bump? What happens if you implement the low processor mode in the project? Also some jitter at max FPS is definitely unavoidable as you computer could be doing any number of things. Even with Low Processor Mode jitter still maybe unavoidable, as the OS gets to determine scheduling, not Godot. Was this Jitter absent in previous versions?

[lawnjelly]

Also for things like this you really need to run it as an exported release and not from the IDE, to compare. When running in the IDE afaik it does all kinds of stuff which could lead to spikes (including communication with the IDE presumably, and there may even be some Sleeps in there when running in the IDE).

[Zylann]

One of the most obvious IDE things is the "remote scene tree", make sure it's not enabled when checking performance.

@SigMA0x How many FPS are you running? Is it possibly related to heat, or for that matter you are on Windows, are there other processes that are causing the bump? What happens if you implement the low processor mode in the project? Also some jitter at max FPS is definitely unavoidable as you computer could be doing any number of things. Even with Low Processor Mode jitter still maybe unavoidable, as the OS gets to determine scheduling, not Godot. Was this Jitter absent in previous versions?

@FeralBytes FPS is stable 60 except for the issue itself. Heat is not a problem for sure (61 C at most on CPU package), but im not sure how to track down if any other processes cause this problem (no browser, or anything like that was active). Low processor mode seems to make issue appear less frequently, but more noticable. I didnt try versrions older than 3.1.1

Also for things like this you really need to run it as an exported release and not from the IDE, to compare. When running in the IDE afaik it does all kinds of stuff which could lead to spikes (including communication with the IDE presumably, and there may even be some Sleeps in there when running in the IDE).

@lawnjelly I double-checked everything in an exported project, profiler screenshots are just for demonstration. The issue behaves identically in editor and in exported release.

One of the most obvious IDE things is the "remote scene tree", make sure it's not enabled when checking performance.

@Zylann It wasnt enabled.

[qdwang]

Same issue here.

And my three computers have different results.

i5 2300 + 750Ti has the spike issue(the spike frametime is about 77ms).
i7 8550u + intel 620 doesn't have the spike issue.
amd r5 3600 + 1660super also has the spike issue(the spike frametime is about 44ms).

Maybe it's related with nvidia card only?