I'm planning on getting a 320GB hard drive for my MacBook White. (2.16 ghz, 2GB RAM. Right now it's at 120GB (Should be 5400 RPM).) Do you think it's overkill/would have compatibility problems/use a lot of battery? Specs for the HD: Hitachi Travelstar 5K320 320GB 5400RPM 8MB Cache? 2.5"