Now, I know plenty of topics on this exist already, but I'd like to voice my issue as well.
Yesterday, I was playing L4D2 with a friend, and I happened to notice that my game was consistently "stuttering:" that is, it gets consistently high (around 60-70) FPS, but once every 1-2 seconds, the framerate drops to about 20 for, what seems like, half a second. Then it goes back to normal, and repeats for as long as a play.
The issue persists from boot-up to shut-down, occurs in single-player, local multi-player, and on servers. It also, for whatever reason, happens in the main menu. This issue does not cross over into other non-Valve games, (but I haven't tried with other official Valve games.)
What I've tried:
1: Turning off VSync. No help.
2: Turning off Multi-Core Rendering. No help.
3: Lowering overall graphics settings. No help.
4: Disabling AA. No help.
5: Setting Paged-Pool Memory ti "Low." No help.
This issue started yesterday, and has persisted on to today. I have not had an issue like this until now. I'm no software engineer, so put everything in English and in layman's terms, if you'd please.