Seagate has begun shipping a new addition to its family of enterprise-class SCSI drives. The 3.5" Cheetah 15K.7 spins its platters at a dizzying 15,000 RPM, yielding an average rotational latency of just two milliseconds. That's still much slower than a high-end SSD; Intel's server-grade X25-E Extreme has an average read latency of 75 microseconds, for example. But the X25-E only goes up to 64GB. This latest Cheetah can be had in capacities up to 600GB, offering nearly an order of magnitude more gigabytes per drive.
Interestingly, the new Cheetahs are only equipped with 16MB of DRAM cache. These drives are likely destined for RAID implementations that'll have their own cache memory, though.
The 15K.7 is available in 6Gbps SAS or 4Gbps fiber-channel flavors. For more on the drive, see the Cheetah 15K.7 datasheet (PDF).