Hi Ben, >Logic 5.5.1 came out before Hyperthreading technology did...therefore it >does not support it. >Logic on a Dual Processor mac does support using both processors,both in G4 >and G5 formats...I don't know if it supports two processors under Windows> though.Good question for Emagic themselves. Thanks heaps Nick, much appreciated... This is the less than impressive response I got from Emagic... " Dear Mr. Fisher, thank you for your query. Emagic have discontinued delivering windows software since nearly two years" It would have been oh-so-hard to just answer the question in the first place.... Do I need to point out that Microsoft manufactured Windows 2000 over 4 years ago and they still provide exceptional support today! In my opinion, vendor support is a must for anything you pay good $$ for...