I know there are numerous posts already about whether to 'clean install' or upgrade to Snow Leopard, but I can't seem to find an answer to my question anywhere. I have two computers that I've already upgraded to Snow Leopard - an iMac that's about a year old (with data on it that has been migrated between macs since Tiger) and a brand new MBP which is unblighted by any migrated data. The MBP seems much faster for the upgrade, but the iMac seems a little slower. My instinct here is to erase my iMac hard drive and install Snow Leopard from scratch, which would presumably solve the sluggish performance issues. My question is this: I have all my iMac data backed up on Time Machine. Is performing a clean install and then restoring my mac from Time Machine going to give me exactly the same problems as upgrading did? Or would it be better to selectively move data back to my iMac after a clean install? If I need to do this the hard way (as I suspect) and selectively bring back my data to leave the junk behind, is there anything I can do before running a clean install to make this more painless? Any help would be much appreciated.