Seagate Technology, the world’s largest maker of hard disk drives, has announced the industry’s first hybrid hard drive (HHD) for mobile computers. The new drive is projected to boost performance and lower power consumption, but according to comments recently made regarding such drives, small amount of flash memory onboard does not help to achieve any of the aforementioned goals.

Seagate’s Momentus PSD (power saving drive) 2.5” hard disk drives are currently available in 80GB, 120GB and 160GB capacities, feature 5400rpm motor, sport 8MB dynamic random access memory (DRAM) cache as well as 256MB of flash memory cache. Seagate declares sustained transfer rate of 44MB/s, 12.5ms average seek time and 5.6ms average latency. The new drives are based on 80GB platters.

The world’s top maker of hard drives claims that the new Momentus PSD’s 256MB flash cache can enable faster boot-up time, higher performance, greater reliability and lower power consumption. However, Seagate does not provide any numbers that would describe and proof the significance of improvements over traditional hard disk drives without flash cache.

Back in September a number of hard disk drives (HDDs) makers said that initial implementations of HHDs are not popular among end-users because they do not provide any tangible advantages. Right now, hybrid drives have 256MB of memory, but if 4GB or so are installed, the flash could hold a lot more storage, which in turn would reduce power consumption and help boot-up time. However, that would raise prices, which may distract customers from the HHDs again.

Nevertheless, Seagate’s Momentus PSD will still get some clients among large computer suppliers, who will be able to advertise the advantages that additional flash cache may enable.