Reply 20 of 26, by Standard Def Steve
I just gave KMPlayer a shot. It actually seems to be a little slower than my usual CoreAVC/WMP11 combo (slightly higher average CPU usage). But then again, so is MPC-HC. I know people love to hate WMP, but at least on an older XP box, it's quite efficient.
Speaking of H.264, if you're running Win7, you should try the updated MS H.264 decoder (which was part of the recent platform update). It's much faster than CoreAVC and LAV Video w/ hardware acceleration. I played a few ~30 mb/s 1080p H.264 MKVs on my Pentium M @ 2.4/GTX-260 after installing the update and saw CPU usage in the 2-16% range. With LAV video decoder, processor usage ranged from 12-34%.
Unfortunately, the MS decoder doesn't provide an easy way to switch HW acceleration on/off, which sucks because I'd like to see how fast it is in software mode.