Samsung Electronics has begun shipping its first hybrid hard-disk drives that combine conventional magnetic storage with flash memory.

The drives are designed for use in laptop PCs and will work with Windows Vista’s ReadyDrive feature, which allows flash memory to act as a temporary cache. This allows the number of disk accesses to be cut, and therefore the drive spends less time in motion and so uses less power.

Samsung claims a 70 to 90 percent cut in power consumption thanks to the system. Because data can quickly be stored and retrieved from the flash memory, ReadyDrive should also allow PCs to wake up faster from sleep mode.

The first three drives from Samsung are 80GB, 120GB and 160GB models and have either 128MB or 256MB of flash memory. That's the same flash capacity as prototypes Samsung unveiled at last May's Windows Hardware Engineering Conference (WinHEC) in Seattle. In July last year Samsung followed up with a prototype that included 4GB of flash memory.

Software support for ReadyDrive exists in Windows Vista only so PCs running other operating systems won't benefit from the technology.

Intel has a competing system that is code-named Robson. It has the flash memory on the PC motherboard and will be included on Intel's new Santa Rosa laptop platform that is due in the second quarter of this year.