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Hmmm, in the System Profiler, check if your SATA bus is clocked at 3 gigabit.

Under Serial-ATA:

460a7c495ce1aa89628eb9db56d0fdbf.png


If it says 1.5, you need to do a firmware update. If it says 3 gigabit, you need to consult with somebody at Apple. My Aluminum MacBook 2.4ghz was TIMES faster than my White MacBook 2.1ghz in responsiveness.
 
Time to sue Apple.

LUL, give them a call and tell then you're constantly seeing beach balls on a NEW install. Maybe they'll tell you something we have overlooked.
 
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