Hello there:
Since I own an E-MU Dance Factory Sound Font, which seems not to work well under DLS in Mac OS X, I run Metro under Mac OS 9 (this is just some introductory information).
It seems that when playing tracks with the Internal Quicktime Synth (whatever bank I choose) the rythm looks a bit jerky (asynchronous performance, with basically no constant rythm, as if a 3 year old kid were trying to play piano).
I tried disabling virtual memory but that gave no results. My computer, far from amazing, I believe it should be yet powerful enough: an iBook G3 600 MHz with 256 MB RAM, which under Mac OS 9.2.2 doesn't run, FLIES. Indeed this problem doesn't arise when running Mac OS X.
Gee. I forgot to tell that I use Metro SE 6.0.8.
Thanks to everybody!