Hybrid Storage Roundup: Seagate Momentus XT vs. OCZ RevoDrive Hybrid vs. Intel Z68
Round 1: 2.5" (and smaller) form factor
With Z68 caching already well covered, we'll hit it with a bit of a twist. While the Z68 piece used a desktop class HDD, this time we will substitute that with the Seagate 7200.4 500GB HDD - a 2.5" drive. This will mimic performance seen when using Z68 caching in a mobile platform, where 3.5" HDD's are a nono.
Along with the 7200.4, we will also evaluate two Hybrid units based on its design. First is the Momentus XT 500GB, which was introduced last year. The second is the newly introduced Momentus XT 750GB. The marketing is a bit fuzzy on these - to get the newer generation XT you'll have to remember that the 500GB is the old and the 750GB is the new. Let's take a deeper look at these units:
...the only way I know how - by field stripping them :)
Here's the 'standard' HDD. No flash is present. The chip at the upper right is actually the drive's RAM cache.
The first generation XT tacked on an extra flash controller (left) along with 4GB of 32nm IMFT SLC flash memory (lower left).
The second (newest) generation Momentus XT uses a beefier SATA 6Gb/sec controller, shrinks and relocates the RAM cache (lower left), and places 8GB of IMFT SLC flash in the upper right.
We took these three units, did the same 3-run tests with PC Mark Vantage, and compiled the results:
At the top is the first generation Momentus XT. It picks up some decent gains in runs 2 and 3, with the Windows Media Center test fully saturating its 3Gb/sec link.
Next up is the new Momentus XT. The first run shows some gains and losses as compared to the G1's first run - most likely due to different HDD NCQ tuning. Runs 2 and 3 on the G2 drive show some impressive gains compared to its older brother, nearly doubling results for all tests across the board. The faster interface allows sufficient leg stretching to beat out even the pure SSD at media streaming.
After the XT's we see a round of runs with the Larson Creek caching the non-hybrid Momentus 7200.4. The first uncached run was similar to both XT's, which is expected as they are all using the same base HDD. Runs 2 and 3 here show yet another step improvement over the second generation XT, except for some areas, where the XT had the benefit of an improved interface.
At the very bottom is the 20GB Larson Creek caching SSD, pure, with no caching at play. This is meant as the reference of how a full SSD would perform as your OS drive. Z68 caching is very effective, as the solo SSD fares only slightly better than the cached Momentus 7200.4 (which is 25x more capacity at 500GB).