The new Cheetah NS drive has more storage capacity, needs less power and should be more reliable. Additionally, the drive is supposed to be up to 21% faster than other 10k RPM drives with 3.9ms average seek times and sustained data rates of 97MB/s.
With the exception of its slower spindle and some changes to the drive head to tune it for operation with a 10K-RPM platter, the Cheetah NS is mechanically identical to the 15K.5. Those mechanics are designed to work with the extremely high precision required by 15K-RPM spindle speeds, but when you slow the spindle down, precision requirements fall as well. That gives the Cheetah NS precision to spare, which Seagate has channeled to increase the drive's storage capacity. When it's spinning at 15K RPM, the drive is capable of cramming 300GB onto its four platters; at 10K RPM, the Cheetah NS packs 400GB onto those same platters. Even the math works out nicely: for a 33% drop in spindle speed, Seagate gets a 33% increase in capacity.Pricing details are unavailable.
In addition to increasing storage capacity, turning down the Cheetah's spindle speed also reduces the drive's power consumption. According to Seagate, the Cheetah NS consumes 34% less power at idle and 33% less during normal operation than its native 10K-RPM products. That makes sense because the drive is using smaller physical disks than its native 10K-RPM counterparts, and smaller platters mean less weight to spin.
Seagate says the NS is more reliable than its native 10K-RPM parts, too. The NS's unrecoverable error rate is apparently ten times better than that of the 10K-RPM Cheetah, and its annualized failure rate is supposedly 17% lower.