Been doing tons of testing while I have machines and time available and came across something fun... When running 10.6 on my late 2008 machines(all I have) I get very unstable behavior of gpu and disk usage IF i have video inputs turned on. The gpu usage and disk usage will randomly go through a couple of seconds of HUGE spiking during which time most active layers will drop a few frames. If I run 10.5 on same machine running same exact content off of same drive etc etc I have no issues whatsoever. I have also noticed this on other machines in the past year but didnt know what to attribute this weird behavior to until now. Turning off the video inputs causes this to go away in 10.6. Everything was identical in the test setup... Anyone else noticed this or have any input?? I would love to use 10.6 more as it performs MUCH better save this issue which makes the extra layer playback capacity of 10.6 a moot point if one is using video input.