The Mac Pro RAID Card offers improved storage performance and data protection to your Mac Pro system — up to 553MB/s of sequential read performance in RAID 0. Ideal for video and creative professionals with demanding storage needs as well as for tower server applications, this hardware RAID option supports RAID levels 0, 1, 5, 0+1, and Enhanced JBOD. It has 512MB of cache and an integrated 72-hour battery for protecting the RAID cache. The card occupies the top PCI Express slot (slot 4) and connects to the four internal drive bays. With the Mac Pro RAID Card installed, high-performance 15,000-rpm SAS drives may be used. SAS drives are sold separately and available with the Promise 450GB SAS Drive for Mac Pro.