I thought I'd share some initial observations LAMP 5.3 on a dual 1Ghz with Mac OS X 10.2 (clean install), Mac AV with AMT8 MIDI interface First impressions are that the performance between LAMP 5.2 on 9.2.2 and 5.3 on OS X 10.2 is identical. I have a busy song which just manages to hit the yellow in the Audio performance meter on both 5.2 & 5.3 5 ES2 6 EXS24 1 ES1 4 Tracks stereo audio 8 Plat Verb 2 Compressor 4 Fat EQ 1 Tape Delay 1 Denoiser 5.3 seems pretty stable. Slightly scary moment with the spinning beach ball for 30 seconds during a copy paste of 4 bars on the same track. No application hangs in around 4 hours of usage Have transferred the song back to 5.2 from 5.3 and back again with no problems for those of you worried about giving 5.3 a go. Was going to bounce the audio to disk - invert then compare - but I'm not really that anal - so I'll leave that for someone with more time on their hands. I guess I would expect some tiny differences due to the way audio is handled by the OS? Not convinced that 5.3 is making any better use of Dual Processors despite the splash screen. It's kind of confusing. The Audio Performance Meter is showing all activity on bar 2 with nothing on bar 1 (same as for 5.2 ). The system CPU is showing both processors bouncing along at almost maximum. Anyone care to comment? I'm not sure that I understand the Audio performance meter with dual processors in 5.2 or 5.3 Logic Control seems to function without problem - then it always has! The on screen anti-aliased fonts option doesn't seem to make a huge amount of difference. Could be down to the fact that I'm on an 18" LCD display with an analogue input that hasn't been calibrated. The cut-out problem with long reverbs and tape delay on DP machines introduced at 5.2 is still present in 5.3. Still have no acknowledgement of my support email(s) from beginning of August on this one. Don't forget to update or copy your preferences as they are not carried across. Kind of annoying having to do this manually. In summary - first impressions are that 5.3 on OS X is fine if your audio/MIDI interface is supported and you don't use REX or Rewire... ...and I recommend you go buy a copy of 10.2... As personally I found 10.1.5 mostly unusable on a dual 1 Ghz. ..and if anyone asks it pissed me off having to pay out £110 for an upgrade 5 months after purchasing a new machine. At least I had the last word by using it as a criteria when advising someone against buying Apple last week. Unfortunately as I use a MOTU 896, REX and occasionally Rewire it's going to be a short while before I move permanently to OS X. Regards, Stuart.