Hitachi Z5K320 review

Much like its desktop hard disks, Hitachi produces two ranges of 2.5in Travelstar disks with different spindle speeds. The Z5K320 has only 8MB of cache instead of the Z7K320’s 16MB, as well as a slower 5,400RPM spindle speed. Although this means performance will be lower, the disk should save a few watts of power at the same time.

Like the Z7320, this disk is a slimline model designed to fit inside netbooks and ultra-portable laptops. It’s slightly thinner than a regular laptop hard disk at 7mm, but you will still be able to install it in a system that has room for a larger 9.5mm disk.

Performance in our benchmarks was less than impressive. Large files were written at 44.8MB/s, one of the slowest write speeds we’ve seen from a new 2½in disk. Writing small files was equally slow at 32.4MB/s. It fared slightly better when reading files, managing 76.4MB/s for large files and 45.9MB/s with small files, but this is still much lower than other disks. Loading Crysis was equally sluggish, taking 40 seconds.

With almost no difference in price between the Z5K320 and Z7K320, the negligible power savings of the slower disk don’t justify the reduced performance. In a laptop you might get only 15 minutes of extra battery life, so it’s definitely worth spending the extra few pounds for the faster disk. Now that netbook and ultra-portable laptop owners have the option of a performance disk, we can’t see a reason to stick with slower 5,400RPM models when upgrading.