Augmenting a magnetic hard drive with solid state storage is becoming a popular idea, but Seagate's Momentus XT was mildly revolutionary when it arrived in May of last year. Today, the company's expanding on the caching concept with a new version boasting 50 percent more storage (750GB), twice the NAND flash (8GB), and a fast SATA 6Gb/s interface to go with it, all for an MSRP of $245. We can't tell you if it's quite as speedy as a pure solid state drive, but some official video demos certainly suggest so — watch it take on an Intel 320 Series (admittedly not the fastest SSD around) as well as some rotary competitors in three videos below. Seagate says the drive is shipping today, and will appear at online retailers soon.