Momentus 5400 PSD Hybrid Drive combines a hard drive and flash memory into a single device. This drive is designed with a 256 MB flash memory to act as a large holding tank for frequently accessed data. Duplicating the most commonly used hard drive data onto the non-volatile cache for instant access provides faster boot-up and performance. Hybrid drive offers many of the benefits of solid-state drive at a fraction of the cost. This hybrid hard drive extends battery life, increase the longevity of your storage and improve productivity with almost instant boot up and data access. Seagate Momentus 5400 PSD hybrid drives is Microsoft Windows Vista-ready.