As a happy owner of a Promise Pegasus3 R6 external RAID enclosure, I was excited to try the new Promise Pegasus R4i internal RAID MPX Module, a unit thats been specifically designed for the Mac Pro.
The Promise Pegasus R4i is a four-drive hardware RAID array that can easily slide into your Mac Pro thanks to its MPX form factor. Adding the R4i to your Mac Pro instantly gives you a ton of on-board storage via four 8TB drives set up by default in a RAID 5 configuration.