Currently running a Celeron 566 at 850 with 256ECC
I'm averaging 5.6 FPS with the following setting
640 * 480(I recommand this resolution if you want TV-Out later)
29.97 Output frame rate
MMX iDTC
Deinterlace Video
Blend instead of interpolate
HQ Biqubic filtering
No Crop, No letter Boxing, Keep Ratio
MPEG Layer-3 256K-bit/sec
Divx low motion 1800 KiloBits/sec
My 366(550) Celeron gets about 3.5 FPS
My 300A(450) Celeron got about 2.9 FPS
so the 850 MHZ was a good boost.