This is normal -- don't worry about it. It's usually the browser.oof_oof wrote:this happens every 2 min. and then looks like the start and end for 90 sec or so.
This in fact, is actually pretty good. The stutter warnings are really just browser warnings, to help you invalidate a test (e.g. pursuit camera photograph, frameskipping photograph, etc) in situations where you absolutely need scientific accuracy in a browser-based motion test. The stutter detector in TestUFO is mainly for that convenience.
It's not the monitor's fault, and will have nothing to do with any games, game engine, etc.
That said, if you get hundreds of stutters during 60Hz even at 100% CPU, then it could be an operating system / setup issue (too much background software). But TestUFO's stutter-detector is not designed for stutter troubleshooting; it's simply a convenient test invalidator for those situations. I have optimized TestUFO's heuristic stutter detector for Chromium-based web browsers, so in GPU-accelerated mode, it's extremely reliable at knowing when browser animations stutters -- I'm one of the only websites to do this reliably -- so much so, that it's capable of scientifically-accurate motion tests when tasked to do that.
(Assuming you're not on one of those "TestUFO Stuck at 60Hz" systems)