These drives generally don't offer much in the way of capacity, either, with many topping out at only 30 or 40 GB. Fortunately, numerous alternatives exist, including drives with 8 MB of cache and spindle speeds as fast as 7,200 RPM. Greater capacities are available, as well, with most new mobile drives offering between 100 and 120 GB, and at least one leveraging perpendicular recording technology to crack the 160 GB mark.

If our test results make one thing abundantly clear, it's that anyone with a 4,200-RPM laptop hard drive with 2 MB of cache could use an upgrade. Even 5,400-RPM mobile drives offer significantly better performance than the 4,200-RPM Fujitsu MHV2040AT with little to no noise or power consumption penalty. To be fair, the MHV2040AT sells for around $60, making it the cheapest drive in the round-up. But you get what you pay for, and spending a little extra can go a long way toward improving performance and increasing storage capacity.