IOMeter — continued

Much better—but not for the Momentus XT. The hybrid's transaction rates fail to scale up as the load increases from a single IO request to 32 concurrent ones. After 32 IOs, the XT's transaction rates jump dramatically, but by that point the drive's already way behind even its exclusively mechanical competition. Native Command Queuing has a queue depth of 32 IO requests, suggesting that the XT's issues here are directly related to its NCQ implementation.

If SSDs do so well with the highly randomized access patterns of our four workloads, why is the Momentus XT scraping the bottom of the barrel? Probably because these workloads are running on the drive as a whole. With an SSD, the entire drive offers lightning-quick access times. The hybrid XT, however, can only provide SSD-like access times with up to 4GB of its available 500GB of storage capacity.

CPU utilization is a non-issue. All the drives are under half a percent with our Core i5-750.

The Momentus XT is no more or less efficient in terms of IOps per percent CPU utilization than the mechanical drives.