Momentus XT: Best Hard Drive Ever?
We're having a hard time drawing one simple conclusion about Seagate's Momentus XT. Its hybrid nature necessitates performance evaluation across multiple runs of testing. If you try to capture the disk's behavior too early, you miss its purpose entirely. At the same time, the company claims that this drive performs similar to an SSD, which it just doesn't.
The Momentus XT is a hard drive complemented by 8 GB of flash memory that operates as a cache. So, when you hit it with a random workload, or a sequence that isn't cached, it performs just like any other 7200 RPM hard drive. That's a worst-case scenario, though.
On the other hand, the Momentus XT can also be nearly as fast as an SSD in the right situation, too. Once it has the opportunity to learn data access patterns and pin data into flash, performance improves significantly. We found that PCMark 7 storage performance typically doubles when compared to conventional 2.5” hard drives after a few repetitions of the workload. However, the most noticeable speed-up comes from booting Windows and launching popular applications. This second-generation model learns faster than its predecessor, and it more effectively minimizes load times.
If you're copying data, then you're probably willing to wait and do something else in the background. However, launching an applications means that you're about to do some sort of work, requiring you to wait until the application becomes available. We can at least say that the Momentus XT accelerates the right sort of task, then, by cutting down on the time you spend waiting. Yes, SSDs are much faster in more situations. However, in its target segment, the Momentus XT offers a great compromise between cost, performance, and capacity.
At the same time, there is hardly any noticeable impact on power consumption. Thus, this drive probably won’t help extend the battery life of your notebook. Nor will its blend of magnetic and solid-state storage hurt power use, either, though.
In choosing between an SSD or Seagate's latest effort, we'd still go with the SSD. To it, we'd add a hard drive in the same tiered configuration you're used to seeing us recommend. But consider a mobile system where you're only able to use one 2.5" storage device. Rather than being forced to pick between the big price tag and low capacity of an SSD or the mediocre performance of a hard drive, you can get as close as possible to blending the speed of flash and capacity of magnetic disks in a single device. Is it a perfect marriage? No. But the interaction between both technologies is unquestionably better than any hybrid effort seen before.
Must you pay extra for the hybrid functionality? Compared to 5400 RPM, 750 GB, 2.5" disks, sure. Those sell for as little as $110 right now. But the Momentus XT is actually less expensive than Western Digital's Scorpio Black 750 GB, which is pretty impressive. So, in environments only able to take a single 2.5" device, the Momentus XT is a great fit.