750GB Seagate Momentus XT Review: The Latest and Greatest Hybrid Drive

What is a Hybrid Drive?

Without getting too technical, a solid state hybrid drive is essentially a small amount of flash memory combined with a traditional hard disk drive. In the case of the new Seagate Momentus XT, you get 8GB of SLC NAND flash memory and a 750GB 7200rpm hard drive with 32MB of cache and a SATA 6GB/s interface.

You never actually see the 8GB of flash storage because the 750GB hard drive is the primary storage space where your data is read and written. A complex set of firmware algorithms configure blocks of commonly used data onto the 8GB of flash so it can be accessed as quickly as possible. In short, a hybrid drive gives you SSD-like speeds when accessing the data you use most. The rest of the time it works like a standard hard drive.

That said, the firmware in the new 750GB Seagate Momentus XT is constantly learning and adapting to your activities in order to "pre-cache" the most important files to the 8GB SSD inside the drive.

FAST Factor: New and Improved

The old 500GB Seagate Momentus XT was the first hybrid drive to use "Adaptive Memory" technology. This is Seagate's marketing term for the previously mentioned firmware algorithms that monitor data access, place "qualified data" in the NAND flash and organize frequently used data and little-used data in a way that minimizes the amount of time the drive spends looking for files.

Adaptive memory technology is essentially what makes a hybrid drive work, but Seagate wanted the new Momentus XT to "learn" faster than before. And so FAST Factor was born. FAST Factor is a combination of two new firmware algorithms: Seagate FAST Boot and FAST Management. FAST Boot basically sets aside a special section of the NAND flash dedicated for booting the operating system. FAST Management is more complicated, but it's a self-learning algorithm that streamlines that integration of the solid state memory and HDD.

Bottom line, the new 750GB Momentus XT offers 50 percent more storage capacity, 1.5X faster performance (thanks in part to FAST Factor), double the NAND flash and double the interface speed of the 500GB Momentus XT.