I've been experiencing game stutter since a while. It happens on all my characters. Stuttering can be unpredictable however it's typically reactive. When WOW Classic TBC Gold I change between my weapons (2h shield to shield and vice versa) I stumble. My rogue also opens stealth, and I stumble when I drop combat. The problem is that it still happens a lot, and a more frequent event when there's number of things going on, such as in a raiding environment. I turned off all addons to verify this, and the results show that there's less stuttering , however it's there, which makes me consider the source of this? My computer is quite good so there's no reason to believe this is the reason. Things I've tried include disabling all addons, tweaking the game's video settings, installing the game, flashing new bios, disabling hyperthreading. This doesn't seem to be working. Does anyone have an idea that could be the cause of this problem? It's really annoying. Imagine your screen going blank each time you switch from a shield to spell reflect.

Update The issue is that despite all the work I did and setting my FPS at a level that kept my card at a lower than 50 percent load, I was experiencing flickering when I ran an Kara raid last night. That's why I decided fully remove Freesync and it appeared to have finally solved the issue.

I disabled it on the monitors in themselves, both are of the same brand, albeit different sizes/models. It is also in my AMD GPU settings. So far that seems to have fully fixed the problem. I'll need to check what other issues pop up.

Original Post: I've experienced flickering issues, but I'd rather label it as complete studdering. It's been happening for a while often, making it difficult to identify. It had reached the point of infuriating me, so I tried to really examine what might cause it.

Long story short, it has been a while since Windows has allowed multiple monitor refresh rates to be used In the past 13 years, Microsoft seems to have tackled a long-forgotten problem in how Windows handles multi-monitor update rates. Windows 10's Desktop Window Manager, (DWM) resulted in frame-skips, and glitches when several monitors had differing refresh rates. Windows 10 2004 20H1's DWM is able to support hardware-accelerated GPU scheduling as of WDDM 2.7, finally seems to have rectified this issue , as evidenced by one user on Reddit.

When I discovered this issue I switched from having a 144hz main monitor with another 60hz monitor. I now have both my monitors at 144hz. It was because I didn't intend to upgrade my system, and my 60hz monitor was due to be upgraded.

But, I was able to do so by upgrading to a bigger main screen. This means that my GPU was now running more pixels , at a greater rate of cheap WOW TBC Gold refresh. My GPU was now required to work, despite being sufficient for the classic WoW. And it was not adequate for the task.