My Macbook pro is running extremely slow lately. It takes me about half an hour to boot (i'm not exaggerating), and i get beachballs at nearly every click no matter what program i'm running. Strangely, from time to time the beachballing stops and i can work without troubles until it hits again. Things i tried: - Replacing the Harddrive with a fresh SSD. Same issues. - Harddrive disk repair / permission repair - Apple Hardware Test (also extended test) - No problems found - EFI firmware downgrade - Running verbose mode and fsck. Nothing strange except two notifications: "SATA WARNING: Enable auto-activate failed" and "AppleAHCIDiskQueueManager::setPowerState timed out after 100202 ms". - Checking the log files when a freeze occurs. No notifications. - PRAM reset It seems like my SATA interface pauses every now and then. When i run a DVD i hear it spinning down and back up periodically, and in activity logger i see strange peaks in the harddisk writes. System info: MacbookPro 5,5 (13 inch of mid '09) OSX 10.6.5 EFI 1.7 Does anyone know what could cause my problems? And more importantly, is there anything i could try to solve my problems? Thanks!