I have a macbook pro 13" 2.53 with 500GB HDD upgraded with latest firmware. Now every like 5 mins or it depends on the process maybe the system lag for 2 seconds like hang with a sound in the HDD when you have bad sector. But I found its OS X problem and not HDD or Hardware issue, cause I tried installing Vista and Windows 7 on it, it works hell smoothly. I only have this lag when I use OS X (Snow Leopard currently) Any idea ppl? any patch? is it well knows issue?