First off, I don't know where I should be posting this so if a moderator feels it should be somewhere else please move it. Ever since Quinn patch some users have had absolutely massive stuttering when in full screen regardless of the frame rate (I get a constant 60fps, uncapped over 250fps). This first occurred on the beta server where the patch was released then the identical problem happened on the live servers when it was released. I started a thread and asked others to share their info, the very few who provided any details seem to be Radeon HD 5000 and 6000 users. Due to the small sample size it's possibly a coincidence. At first I thought it was both with and without vsync but it seems it's only with vsync. The reason it seemed to stutter without vsync as well is because the tearing is absolutely tremendous without vsync and causes its own stutter-like effect. I tried every combination of settings to see if anything bypasses it. Sure enough windowed mode avoids the problem entirely. All signs at this point seem to point to vsync, but to throw a wrench into this all, when spectating the stuttering does not occur. So why not just use windowed mode? First of all a problem shouldn't be ignored just because there is a band-aid fix, secondly I use 2560x1440 in-game (for down-sampling) and in 1920x1080 on my desktop. That means I'd have to give up down-sampling to use windowed mode. It's not a big deal but still a loss. I have been in contact with a support specialist from Riot since March 1st and needless to say he has absolutely no idea what to do. I've sent logs of absolutely everything in to them (DX, processes, game logs, etc, etc) and at this point we're still at square 1 and he's asking me for stupid things such a process log again with my antivirus and firewall uninstalled this time. I tried to record a video with FRAPS to show him, but as soon as recording begins the game goes smooth, I **** you not. Then when I press stop recording the stuttering resumes. This stuttering is at a consistent timing, not random, so it still seems likely to be at least partially related to vsync. This is a technical problem that's beyond their support agent's understanding. A stuttering issue that's possibly related to vsync and Radeon 5000/6000 drivers, more specifically, possibly a program incompatibility with those drivers/vysnc. Between all the users on Guru3D I'm hoping we can figure out precisely what the problem is. TL;DR: Some users have had heavy stuttering in full screen (regardless of frame rate) with vsync since the Quinn patch. There were very few who gave me their details but the few who did were Radeon HD 5000 and 6000 users, coincidence maybe. Riot support is clueless and have not solved it since a month ago when I contacted them.