9.5 Versus 12.5 mm: Which Notebook HDD Is Right For You?

9.5 mm: MK6465GSX, 640GB

We picked two Toshiba hard drives for an apples-to-apples comparison. The first product is the MK6465GSX, today's 640GB drive. There is also a 750GB model. We haven't received this drive yet, but differences compared with the 640GB should be minor.

The 640GB model uses two platters and stands just under a 9.5 mm height. The spindle speed is 5,400 RPM, the standard rotation rate for mainstream and high-capacity laptop drives. Toshiba specifies a MTBF rating of 600,000 hours, but it's hard to compare this because Seagate and WD do not publish any reliability specifications. Toshiba's 3 Gb/s SATA interface and 8MB cache are check box items, as is the operating temperature of 5°C to 55°C. A few drives can run at up to 60°C, but this shouldn't be relevant in most environments. Toshiba also offers models at 160, 250, 320, and 500GB capacities.

We measured a maximum read transfer rate of 91 MB/s. That’s excellent for a conventional hard drive, and although the three-platter unit delivers a bit more throughput, this two-platter model wins on access time and application performance. Amazingly, both drives show almost identical idle power consumption and maximum read speeds.