set your raid 0 stripe size to 32kb.
the main strength of raid 0 is that it reads and writes to multiple hard drives at the same time. it has more "hands" to work with so it can handle higher data loads derived from...
it's more expensive because it is the fastest cpu available for the alienware's m9750 chipset (and any other mobo based on the same chipset) so they make their money that way.
the t7700 is not compatible with your laptop as it uses a different socket and has a different fsb so it simply won't work. you want to look at the even model numbers (like T7600) as they are the 667mhz fsb that are compatible.
if...
