Random screen stuttering / flashing

[Targa]

Issue: At random times the game will "stutter", which appears (to me) to be the game losing vertical sync with the monitor's refresh rate. At times it can be so bad that I actually see my monitor "flashing" on and off, as if the refresh rate is dropping to 20 or fewer times per second. The issue vanishes within 1-2 seconds.

I've done a bunch of searching and problem solving. Things I've tried:

Vsync: on / off
Disabled mod: WaiTex
Nvidia control panel: Prefer maximum performance
Video memory usage: All / High / Medium
Graphics Quality: Normal / Low

None of the above solved the issue. Video memory usage without WaiTex is ~800 Mb of 4096, with WaiTex enabled it's ~1500. My video card is an Nvidia GTX 980, which can run Factorio in its sleep. I ran across this post: viewtopic.php?f=49&t=16503 in which Athmagor states in the 5th paragraph:

What it looks like is that without VSync the game every now and then desyncs itself from the monitor refresh and gets into not really tearing but more of a stutter. After 2, 3 seconds it gets back into the margin of synchronicity and the gameplay is smooth again.

This sounds suspiciously like what I'm experiencing. Except in his case he said he solved it by enabling vsync, wheras I've had it enabled the whole time (except when testing the issue). So I would modify the above statement to say, "It appears the game every now and then desyncs itself from the monitor refresh rate and stutters, then after 2 or 3 seconds synchronizes itself again".

Windows 7 x64
Intel i7 920 @ 3.54 GHz
Nvidia EVGA GTX 980 4gb Superclocked
System RAM - 12Gb
Game Installation is on an SSD drive

Any help would be appreciated.

Edit: Just tested with FRAPS, and the game is dropping from 60 FPS to ~45 FPS during the lag spikes. Driving in my car back and forth I can cause it to happen every 20 seconds or so. I doubt it's a graphics issue, as even with the graphics quality set to low it still happens. Seems more like the game engine itself is stuttering when updating entities or something. I really don't know what to think at this point. I can play any high-end game just fine (Fallout 4, max settings, lots of mods, etc... for example).

[Rseding91]

When you switched VSync off did you restart the game?

I run with vsync off, video memory usage All and experience no such issues on my GTX 970 which has an equivalent amount of VRAM.

Do you have desktop composition enabled/disabled (the transparent edges on programs)?

Do you have any other software running that does video hooks?

Do you experience the issue in windowed mode, fullscreen, full size, or any combination?

[orzelek]

Additional thing might be mods - if they spike in time usage then you will "miss" the vsync window and frame will be dropped since it will need to wait for next one.

[Targa]

Desktop composition is disabled. Pretty much everything is disabled with Windows 7. I'm in what might be called "Classic XP mode" (no Aero, themes, etc).

No other software is running in the background other than Steam.

Issue is present in both fullscreen and windowed modes.

When I switched vsync off I did not restart the game. After reading this I tried that, and indeed the stuttering went away and the game ran at a steady 60 FPS, along with having a very noticeable horizontal screen tearing/blurring about half an inch wide every time my character moves. Unfortunately this is worse than the stuttering issue and is an unacceptable solution for me.

Issue happens even with all mods disabled (although it appears to not drop quite as many frames, dipping to ~50 fps when stuttering rather than ~42 fps).

So it does appear to be an issue with the game's graphic engine missing the vysnc window and dropping frames until it can resync itself. Will welcome any other solution. I also tried disabling in-game vsync and forcing it through Nvidia CP as well as D3DOverrider, both of which failed to properly enable vsync in the game.

[Rseding91]

Try this once: enable desktop composition and disable vsync.

[Targa]

Try this once: enable desktop composition and disable vsync.

Well, that was quite an adventure, and one that I'm not hoping to go through again any time soon. I had to run services.msc and enable Desktop Manager Window Manager Session Manager service, then choose an Aero theme (yuck!), then find and enable desktop composition, at which point Windows 7 decided to turn off ClearType for no apparent reason. At any rate, the end result of the test was that there was no more screen tearing in-game with vsync off. There was no more fps drop to ~42-ish or so (FRAPS reported a steady 60 fps at all times). However, although FRAPS showed 60 fps, I still observed "screen flashing" (indicating dropped frames/out of sync) at those times I would normally have experienced stutter. It appeared as if a rapid strobe light was flashing in my eyes for a couple of seconds, every 15 seconds or so.