Anandtech is carrying the news (sourced from X-Bit Labs) that Seagate will be ceasing production of three of its four Momentus 7200RPM disks: the Momentus 7200.4, Momentus 7200.2, and the Momentus Thin 7200. The company will continue to manufacture slower 5400rpm drives, but the 7200rpm format makes less and less sense with the availability of hybrid drives, SSD-backed caches, and actual SSDs.

We've written a lot on how SSDs work, and their dominance of the laptop space seems assured at this point. 7200rpm drives are offered by just about every laptop OEM as a performance upgrade over cheap-and-slow 5400rpm drives and full SSDs, but the incentive for consumers to choose them versus a small SSD-based cache (like Intel's SRT) is rapidly eroding. A small SSD cache typically doesn't add that much cost to a laptop, but the performance boost for most workloads will be much greater than upping a spinning disk's rotational speed from 5400 to 7200rpm.

Caching aside, SSDs themselves are rapidly eclipsing spinning disks in the mobile market, whether in the traditional 2.5-inch form factor or the newer mSATA "stick" format. Most consumers foregoing an SSD for a spinning disk on a laptop are seeking the lowest possible cost on their hardware, and that means 7200rpm 2.5-inch drives don't really fit into very many buyers' plans anymore. An "as cheap as possible" laptop buyer would want a 5400rpm drive; anyone with even a slight inclination toward performance would choose a caching solution, a hybrid drive, or a full SSD over the tiny incremental improvement of a 7200rpm drive.

Even though Seagate is ditching all of its 7200rpm "pure" hard disk drives, the company is still focusing on performance with its hybrid Momentus XT product line, which marries a 7200rpm platter with a chunk of NAND flash and uses the NAND as an extended disk cache. However, Seagate's lack of consumer SSDs puts it in an awkward position of not having a really pretty girl to bring to the SSD dance—you sell the technology you have to sell, and Seagate will obviously be pushing hybrid hard disk drives in the near future as a less-expensive performance option for people focused on value. The performance isn't that spectacular, though: previous Momentus XT drives just aren't very fast.

Seagate could get itself an SSD without too much effort, however. Back in January, we spoke with representatives from LSI/Sandforce at CES, and one of the things the Sandforce representatives touted about their SSD controllers was how OEMs could easily construct their own SSD solutions around them. Of course, shortly after this a representative from Samsung pointed out that not controlling the entire controller/NAND supply in a disk's manufacturing can lead to integration issues, especially as NAND is only getting smaller and potentially more fiddly.