A few weeks ago Seagate announced its first 5mm 2.5-inch hard drives and it seems to be getting a lot of attention. Big players are lining up to stick the ultrathin drives in their new ultrabooks and even tablets.

In fact, Seagate has demoed the new 500GB drive in a prototype Android tablet. Although it sounds like overkill and we still think hard drives in tablets are sort of pointless, it is an impressive feat of engineering. Ultrabooks are the real target market, and with prices starting at $89 for the 500GB drive, it is still a lot cheaper than SSDs, which are usually employed in ultrathins.

Although SSDs are much faster, the ideal approach is to use both - a small SSD cache drive along with a 500GB ultrathin HDD.

Asus and Dell have already signed up and they will use the drives in upcoming notebook designs and the rest of the industry should follow suit. Of course, Western Digital has 5mm drives of its own, with the exact same pricing for the 500GB model. However, Seagate also has an even cheaper 320GB version.