I have a home studio music workstation PC running XP Home with an ABIT AI7 motherboard and a P4 3GHZ S478 800FSB 1MB with 2GB memory. I recently made the mistake of trying to improve the performance of music software by upgarding my motherboard and CPU to use Athlon 64 X2 4600. Unfortunately it was a disaster ( I guess too many changes to the HAL, etc). Since I have a lot of programs and plugins I was not up to doing a clean install. I even briefly considered upgarding to Vista.... Well, I re-installed the original MB and CPU and now I am back to 'normal'. I have, I think, one more option to consider: upgrading the CPU to the fastest S478 CPU I can find - P4 EE 3.4GHZ S478 2MB. Is it worth it? Can I expect I noticeable speed/performance improvement? I think that XP will allow the CPU change even if it requires re-activation which is OK with me. I would like to get opinions. Thanks!