If you play H.264/AVC material, you can try http://wiki.videolan.org/WindowsFAQ-0.9.x#H.264.2FMPEG-4_AVC_playback_is_too_slow I've tried that no effect VLC does all decoding in CPU, while MPC can use proprietary codecs that uses GPU. my friend also test it (since he curious about ts file) he's spek...
My Spek: Intel Celeron 420 i945GP ATI HD 3450 2GB RAM DDR2 Running WinXP SP2 and the rest before upgrading to HD 3450 I'm using Onboard IGP (945), and using VLC 0.86 it plays perfect, no stuter no lag, and CPU usage is arround 50-80% with MPC the video can't even play normally after upgrading to 345...