There has been much speculation that a new generation of hybrid flash/hard disk drives was right around the corner, and Provantage confirmed it today: The reseller posted a family of “Momentus XT” 2.5″ laptop drives for sale on their web site, shipping in 3-4 weeks. Many other sites began listing the drives as well, and The Register got the scoop, benchmarks, and official comment.
Hybrid Hard Drives: Take Two
The new drive family sports 4 GB of NAND flash and 32 MB of DRAM operating in tandem as a cache. It is a 2.5″ model, and since Seagate doesn’t currently produce a drive fatter than 9.5 mm one can assume it is a two-platter model and will work in most laptops. It sports a 3 Gb/s SATA interface with native command queueing (NCQ), nicely up to date but nothing special.
There are three models in the Momentus XT line, all with the same 4 GB/32 MB cache:
| Model | Capacity | Street price |
|---|---|---|
| ST92505620AS | 250 GB | Unknown |
| ST93205620AS | 320 GB | $111.59 |
| ST95005620AS | 500 GB | $133.84 |
Unlike the previous-generation H-HDD drives, the new Seagates have fully-integrated SSD cache featuring speedy SLC chips. The dependence on the host operating system to make caching decisions was one of the things that sunk H-HDDs in the past, but this looks to be an entirely different solution. Seagate looks to have integrated the flash as an extension of the RAM cache and is using the drive’s own logic to determine what to cache and when. This will not only be more-generally applicable (not requiring a special OS) but will likely work better, since on-drive cache management has improved greatly over the years.
Stephen’s Stance
Assuming I’m right about Seagate’s fully-integrated cache architecture, this drive ought to blow away everything else on the market. The Register includes test results showing SSD-like performance for many workloads, yet this drive is half the cost and twice the capacity. It beats the 10k VelociRaptor drive in every test and will absolutely smoke any “normal” 7200 or 5400 rpm laptop drive. Feel free to exclaim “wow!” at this point.
How excited am I? How about this: Although I upgraded it just last month with a 640 GB Toshiba hard disk drive, I want a Momentus XT in my MacBook Pro. I’d rather have one of these than a straight SSD, considering the mix of performance, capacity, and price. Maybe I can move the Toshiba into an MCE Technologies OptiBay?
I will be watching this release with great interest. Word is that Seagate will officially unveil the drive in a webcast on Wednesday, May 26. I look forward to a flood of performance tests from my favorite consumer sites, and expect it will interest the enterprise guys, too (this means you, Howard!) Could hybrid drives finally be getting real?