When it comes to mobile storage, 1.8" HDDs are both loved and cursed by consumers. The small drives allow for a relatively large amount of storage in a small form factor, however, the drives spin at a lethargic 4200 RPM.

The rather slow spindle speed isn't much of a problem with portable media players (PMPs) such as the iPod Classic or Zune 80 -- the problem comes when the drives are installed in ultra-portable notebooks like the Apple MacBook Air which uses an 80GB 1.8" HDD spinning at 4200 RPM.

Apple tries to get around the performance issues by offering a 1.8" 64GB PATA solid state disk (SSD) for increased performance, but that drive option also adds $999 to the price of the already expensive notebook.

Lenovo dispensed with HDDs altogether on its new ThinkPad X300 and only offers a 1.8" 64GB SATA SSD.

Toshiba looks to give mobile devices everywhere a boost with its new 1.8" MK1216GSG (120GB) and MK8016GSG (80GB) HDDs. Both new drives meet the new SATA 2.6 specification and incorporate a micro-SATA connector. Most importantly, the new drives spin at 5400 RPM -- a speed that was once reserved for larger 2.5" HDDs in the mobile sector.

Both drives feature 8MB of cache and offer data transfer rates of 489 Mbits/sec. Toshiba lists average seek time at 15ms for both drives.

"The portable computing market is looking for an uncompromised computing experience in small and light-weight storage solutions," said Toshiba Storage VP of Marketing Maciek Brzeski. "With enhanced features for the mobile environment, these new 1.8-inch HDDs enable mobile system manufacturers to reap the benefits of high-capacity magnetic storage, along with better power efficiency and ruggedness."

The most likely target for the faster drives from Toshiba is Apple's MacBook Air. The availability of faster, higher-capacity drives could blunt some of the performance advantages of the expensive SSD option on the MacBook Air.

Likewise, Lenovo may be wise to offer the drives on its ThinkPad X300. Reviews for the 13.3" notebook have been overwhelmingly positive, but the high $2,500 price of entry is a big turn-off to some. Toshiba's drives could easily drop the ThinkPad X300's price entry well below the $2,000 mark.