Western Digital ships first 5mm ultraslim drives -

Western Digital is entering the hybrid hard drive market in style, with an ultraslim 2.5-inch SSHD designed for Ultrabooks and other anorexic devices. 

However, Western Digital is not ditching traditional hard drives. SSHD will be marketed as part of WD’s Black Series, while plain HDDs will be sold under the Blue brand. Both are just 5mm slim and they should fit even the skinniest ultrabook designs out there.

Western Digital had to cut a few corners to make the drives so slender. Both use a proprietary edge connector, which delivers power and a traditional SATA interface in a slimmer package. In addition, the drives only seem to come in one size, 500GB. 

The SSHD is definitely the more interesting of the two, as it should bring the best of both worlds on a budget. The Blue drive sells for $89, which sounds reasonable, but there is still no word on Black SSHD pricing. WD did not say how much NAND cache it plans to use on the Black, but our bet is 16GB.

Although both drives are 5400rpm units, WD claims they are 10 percent quieter than competing 5400rpm drives. Additionally, they weigh just 74 grams, which means they are 36 percent lighter than comparable 7mm drives. They also need 47 percent less volume, making them an even better choice for cramped ultrathins.