Originally posted in another thread in the Peripherals section: I've been seeing what I'd call "interesting" performance issues with the Pegasus2 enclosures that I have connected to the new Mac Pro. Each is on its own Thunderbolt channel. One has 4 drives in it, with 2 RAID0 volumes. The other has 2 drives in it, also in a RAID0 volume. These RAID volumes were created using the Promise utility, not OS X. The drives in question are 7200RPM SATA2 or SATA3; they're certainly not the fastest things available. What I've found with Blackmagic is inconsistent read and write results. Sometimes a volume will get 200+MB/s reads and writes. Other times it'll stumble with the test first starts, and stay around 10MB/s (not a miss-print). It applies to both enclosures. As a test, I nuked two of the volumes, reset the drives to "Pass-Thru" mode, and recreated the RAID0 volumes in OS X software. The results? Consistent performance numbers of ~250MB/s on reads and writes. Not necessarily better, but reliable. At this point, I can't recommend the Pegasus2's internal RAID controller if performance is needed. Certainly if you intend on using RAID5, which OS X doesn't support internally, then the enclosure's controller would work. But if you're just doing RAID0 or 1, there's really no reason to not use software RAID. The CPU in the Mac is certainly significantly more powerful than what's in the enclosure, and handling RAID/storage requests won't make it break a sweat at all. What have others found?