The hybrid delivers impressive performance at a low price.The Momentus XT is a 7200-rpm serial ATA (SATA) hard-disk drive combined with 4GB of SSD capacity and 32MB of DDR3 cache memory. Seagate claims the Momentus XT is 80 percent faster than traditional 7200-RPM drives. The Momentus XT works on PCs and Macs.
I am always sceptical of manufacturer speed claims, but if I were to draw up a list of companies whose claims are typically the most outrageous, Seagate would be pretty near the top.
I think the bootup speed claims are interesting. In order to significantly improve boot speed, the majority of the boot code would have to reside in the fast area of the disk (presumably the SSD part). This would clearly limit the amount of space available for other activities.
For general performance improvements, fast page-swaps are probably the most important factor and flash memory isn't normally considered suitable for this due to wear-out issues.
If you have a 64bit OS, the extra cost of this drive could probably be better spent on more memory.