Flash hard drives are expensive, but gaining popularity. Unfortunately they still don't meet the same value levels that current hard drives can. The price of flash based disks is around 25x more expensive per GB. A synergy of these two technologies offers a halfway point that takes advantage of the best of both worlds.

Hybrid hard drives, or H-HDD combine these two technologies to offer an increase in performance as well as an improvement in power consumption. The flash memory is stored onboard the hard drive and picks up where a normal hard drive leaves off. Speed can be increased dramatically because there is no mechanical latency in the memory like there is in the hard drive. Power consumption can be improved because frequently used application data can be stored and then pulled from the flash memory.

These advantages apply mostly to notebook hard drives. Laptop drives are much slower than desktop hard drives, and power drain is a big concern. With these additions H-HDD manufacturers hope to make laptop hard drives reach similar speeds to their desktop counterparts.

Currently, hybrid hard drives require that you run Windows Vista, not because it needs Vista, but because it needs ReadyDrive, a feature that comes with Vista. Which data is stored on the flash part of the drive is controlled by the operating system, and in Vista, ReadyDrive takes care of this. ReadyDrive sees how you use your programs and which ones you use the most, it then puts the most heavily accessed application data onto the flash memory part of the hard drive.

Power is saved when there is a read/write done onto the flash portion of the disk. Flash media requires much less power because there is no motor needed. However, when the data is written to the disk the motor still needs to be used and therefore uses that power that was saved.

The flash media suffers from a slower transfer rate than the main part of the drive, but with its much faster access speeds, makes up for this. The fast cache that has become an integral part of hard drives is not replace in these models, but the flash part just complements the functions of the drive.

In actual use there is not really much advantage to this kind of hard drive. Although it promises to improve performance and save a lot of power it really does very little in the real world. Just wait for flash-only drives to come down in price, which is already happening, or for now just use a traditional model.


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