To test read/write speeds, I used several benchmarking tools, starting with ATTO Disk Benchmark Software. The Seagate Momentus XT showed a read speed of 96MB/sec, with a standout write speed of 92MB/sec.
Next, I tested the new drive with Simpli Software Inc.'s HD Tach benchmark software. Those tests showed an average read speed of 83.7MB/sec, a burst speed of 213MB/sec, a random access time of .3 milliseconds and a CPU utilization rate of 8%.
I also tested the Momentus XT with the HD Tune 2.55 hard disk utility, which reported an average data transfer speed of 78.6MB/sec, a data transfer burst rate of 123.3MB/sec, an access time of 16.5 milliseconds and a CPU utilization rate of 4.3%.
By comparison, Western Digital's fastest hard drive, the VelociRaptor VR200M (600GB model) model, has a 145MB/sec. read rate and an 82MB/sec. write rate, with a random data access time of about 7 milliseconds. (The company's earlier 300GB VelociRaptor model had a 110MB/sec. read rate and 81MB/sec. write rate, with a random data access time of about 10 milliseconds.)
To test the Momentus XT drive's write speed with a real-word application, I copied a 2GB file folder with 544 .jpg images from the desktop to the My Documents folder, which was completed in a fast 35 seconds, just 9 seconds longer than it took Intel's X25-M SSD to transfer the same folder. The Seagate may have taken a bit longer, but it costs hundreds of dollars less than the X25-M SSD and offers hundreds of gigabytes more storage.
Although it's been touted as a hard drive with SSD speed, the Momentus XT can't really meet or beat a full-fledged SSD on read performance. For example, I tested OCZ's Apex SSD with ATTO's benchmark utility and it showed a 221MB/sec sequential read rate and 160MB/sec sequential write rate. The Intel X25-M SSD, considered by many the standard in consumer-class SSDs, clocks in with an average read speed of 190MB/sec. and a 70MB/sec write rate.
Price advantage: Momentus XT
But here's the rub. The Agility Apex SSD with 60GB costs $159 at online retail sites, such as Newegg.com. The Intel X25-M SSD with 80GB of capacity costs about $215 retail. Even Intel's most affordable SSD, the X25-V, retails for $125, but you're only getting 40GB of capacity.
The Momentus XT with 250GB of capacity costs just $113, and a 500GB model goes for $156. So you are getting top hard drive read performance and even better write performance than some SSDs at a very reasonable price.