Describe the problem. Be as specific as possible!:
My windows XP computer is back to the stuttering - but now it's mucho unplayable, 1 second smooth, 1 second without frame updates.
I defragmented the MS folder and restarted, what I see is if I hold up my watch to the monitor, every time the second ticks over, it switches from updating frames to not updating frames and vice versa.
It's a 2.8GHz P4, only place it ever used to dip below max framerate is FM1CH1 and Boomers.
Win 7 computer is seeing the same oscillations in CPU usage but it's not affecting the framerate.