The first hybrid hard drive on the market is from Samsung, which handily enough manufacturers the flash memory used within the drive itself. Physically the drive looks and acts like a standard 2.5-inch SATA hard drive with a standard 8MB buffer.
The magic comes in the form of 256MB of extra NAND memory, which acts as a ReadyBoost drive when used with Microsoft's Windows Vista. That's right: it's only of real use with Vista. Other operating systems see the drive as a standard unit, and Samsung doesn't even seem to make use of the NAND as a large buffer.
Having said that, the Samsung HM16HJI puts in a good performance for a 2.5-inch drive, with sequential access reaching 45MB/s and random access around 30MB/s, matching desktop 3.5-inch drives in terms of sheer performance.
In comparison to Turbo Memory, though, the drive is something of a disappointment. Considering this is the top of the range model, the 256MB NAND flash is half that of what Intel will offer as the basic Turbo Memory option. What's worse is that the smaller drives use just 128MB of NAND flash. It's all rather stingy.