1 500GB drive vs S/W RAID 0 with 2x250GB

[M A V I C]

Depends on the drives, most likely. The 500GB probably performs better than a single 250, but a RAID0 would help, but it being a software RAID0 might negate any performance.

I would stick with the 500 for reliability. I tend to shy away from RAIDs unless they're hardware and with a good controller.