Western Digital's newish VelociRaptor SATA hard drive speed tests when configured in a 3 drive RAID-5.

The burst speed recorded was robust 598MB/sec, according to HD Tach, which is about on par with what we've seen from WD's Raptor WD1500 line in this configuration. However, average read performance is through the roof, with a 209.4MB/sec land speed record set for what we've seen in our labs and about a 33% performance gain over what we've seen with Raptor WD1500 drives in RAID 5 on the Areca controller. Finally, random access clocks in at a snappy 7.2ms.