Promise Pegasus R4 8 TB
|Promise||Pegasus R4 4 TB||Pegasus R4 8 TB||Pegasus R6 6 TB||Pegasus R6 12 TB|
|Devices||4 x 1 TB||4 x 2 TB||6 x 1 TB||6 x 2 TB|
|Hard Drive||Hitachi 7K1000.D||Hitachi 7K3000||Hitachi 7K1000.D||Hitachi 7K3000|
The four-bay version of Promise's Pegasus is more affordable, offered in 4 and 6 TB configurations. You'll pay $1150 for the 4 TB R4 (versus $1800 for the entry-level 6 TB R6). Aside from its lower price and two-fewer drive bays, there's very little else distinguishing the R4 and R6 families. Promise even uses the same Hitachi Deskstar hard drives in them both.
Crack open the R4 and you find the same motherboard and power supply seen in the R6.
Eliminating two drive bays from the R6 does impact performance, though. In RAID 0, the R4's sequential reads top out at ~635 MB/s, representing a closet-to 33% drop from the R6. Sequential writes in RAID 0 only drop about 18%, from 635 MB/s to 535 MB/s.
RAID 1E and RAID 5 performance are mostly unchanged. The only exception is that sequential reads in RAID 5 peak at ~460 MB/s, about a 70% drop from the R6’s 780 MB/s.