crookedvulture writes: Seagate announced its third-generation hybrid drives last month, revealing a full family of notebook and desktop drives that combine mechanical platters with solid-state storage. These so-called SSHDs are Seagate's first to be capable of caching write requests in addition to reads, and the mobile variants are already selling online. Unfortunately, a closer look at the Laptop Thin SSHD reveals some problems with Seagate's new design. While the integrated flash cache reduces OS and application load times by 30-45%, overall performance appears to be held back by its 5,400-RPM mechanical component. Seagate's last-gen Momentus XT hybrid spins its platters at 7,200-RPM, and it's faster than the new SSHD in a wide range of tests. The upcoming desktop SSHDs will also have 7,200-RPM spindle speeds, so they may prove more appealing than the mobile models.