I've got a 2 drive 640GB Black Caviar RAID that I want to set up as just an OS and apps boot drive. I realize larger block sizes have more through put but waste disk space, and smaller sizes save space but are less efficient. My user folder (mail, media, itunes, video, docs) will be on a separate drive. (1) So how do apps and OS files load at boot time and runtime? (2) If apps like CS4 are large apps does it not make sense to set 256K as the block size? (3) Or does OSX use many small files thus needing a smaller block size? Drive space is not an issue. I realize the default 32K was designed as a mixed bag for the all around average user. Does anyone have experience running a RAID0 as just a boot drive?