this is exactly why no one uses their setups for video anymore..., too many to choose from and the quality of playback is random..
frogger NG and amp2 must be the fastest ones here, but moovid pro aint bad either..
but since every of theese is buy ware means i cant really recomend em yet, as basically u need em all which is sad....1 should be enough and it should be internally in the os...and free if u ask me, beyond that i am a frogger nG owner + amp and moovid.
anyway about the problems mentioned here , the 040 is slow and most likely u will need a scsi II drive or a powerflyer for the playback drives,
clocking the cpu to 33mzh (if 040) is wise, but 040/40 aint always..., the memory bus to 66 is also wise, but be sure to rip off the fan + cooling rib u have on the ppc now , exchange it with bigger and better ones and put new cooling paste on the TINY cpu inside

i only have problems with "fast forward" functions in the divx players...all other is ok, and streams fine..., when i FF everything stops and suddenly goes 3x (or more) speed for a few secs, so its not really big issue......imho.
hope this helps, and i pasted a overclocking page for cppc and bppc here some weeks/month ago, so do a search in the forum about PPC topics, or i will come back to you with the link, its fairly easy but if u want to change the core VoLT and switch from 040 to 060......well i have NO experience in that...