I don't mean to create a redundant thread for this issue (documented here), but from what I can tell, 13" and 15" uMBP users now have a solution to the 'beachball' issue that plagued those machines - downgrade to EFI 1.6. Ok, so SATA will 'only' run at 1.5 instead of 3.0, but no beachball issues. Now, what about uMBP 17" owners? If you have a uMBP 17" and you replaced the stock harddrive with another harddrive or a SSD, have you experienced any 'beachball' issues? For lack of better definition, 'Beachball issue' would be the computer freezing for some period of time (10-30 sec) now and then.