I'm buying a 2nd hard drive for my later 2008 MacPro. I haven't decided what size I'm getting, probably something around 500GB since my main hdd is 500GB. At any rate, this one will be used primarily for Time Machine. Is it hugely beneficial to get a drive with a 32 mb buffer over a 16 mb buffer? If it matters, I'll be putting a 1TB into the 2nd bay and the Time Machine HDD will be in the third bay. Not sure whether or not that factors into all this.