@marlyn When this happened to me, it kept getting worse and worse. Running at lower resolutions helped a bit, but then the power supply gave out. I am now convinced the graphics card issue was a symptom of the failing power supply.
@marlyn My issue was on a box running GNU/Linux. I don't run Windows on my own PCs anymore.
@skquinn
Strangely enough, so far I've only noticed this issue on my linux partition? I haven't noticed anything funny going on when I've been booting up windows.