To see if your G4 Sawtooth is dual-CPU compatible, go to... http://www.sonnettech.com/support/errata/duet_errata.html ...follow the documented procedure and see if your system's UNI-North chip is rev 7 or better. There's also a freeware app that you may be able to download from Versiontracker to do the same (or email off list and I can send it to you.) If so, then you may want to check out eBay or similar places to get a dual G4 CPU. Be sure to get the heatsink as well. On my wife's G4-500 Sawtooth, I swapped out the original CPU for an Apple Dual G4-500 module and she noted immediate performance improvement in Photoshop, printing, scanning etc. under OS 10.2 -- total cost < $100. Now we can wait for the 2nd rev of 970-based systems in January 2004 before buying :-) Regards, Jim