It's been over a year since I reviewed Seagate's first hybrid hard drive: the 500GB Momentus XT. At the time I felt that it wasn't nearly as good as an SSD, but likely the best 2.5" hard drive money could buy. Armed with only 4GB of SLC NAND acting as a read cache, the original Momentus XT delivered VelociRaptor performance in a much more power efficient package. 

Since then Seagate hasn't updated or expanded its line of hybrid HDDs at all. I kept hearing rumors of new drives coming but nothing ever surfaced. More recently Seagate announced that the next version of the Barracuda XT will be a hybrid drive as well.

Today Seagate is announcing availability of its second generation Momentus XT. Now at 750GB with 8GB of SLC NAND (once again, as a read cache), the new Momentus XT is a definite evolution over its predecessor. With a larger NAND cache Seagate can be more aggressive with its caching, not to mention the improvements to the mechanical side of the drive as well. The entire package is still not nearly as fast a value SSD, but it's doing much better than mechanical (3.5" included) hard drives in our tests.

Write caching is still not enabled on the NAND, however Seagate is planning on enabling it via a firmware update sometime in 2012. I've seen results from an early version of the write caching firmware and the improvement is tangible. 

The 750GB Momentus XT will be available at a MSRP of $245.

We're still hard at work on our review of the drive, expect to see it later this week!

Update: Our review is live!