Massive FPS Drop on High Spec Rig ?

[mZLY]

No, it's overclocked through Catalyst Control Centre. Have reset it to factory clock speeds and the problem persists though.

I've had it for over a year with no problems now.

No, it runs Crysis 2 (max settings), Battlefield 3 (max settings) and ArmA 2/DayZ mod (high settings) without issue.

The fact that reading a letter (probably the least GPU intensive part of the game) caused the FPS drop makes me think the problem is not with my graphics card.