The Lenovo ThinkCentre A51's black case, which still carries the IBM logo, isn't as big as most "small form-factor" computers, but it houses a complete PC that can meet the computing needs of basic business users without exacerbating cubical clutter.

Equipped with a 3-GHz Pentium 4 531 CPU and 512MB of DDR2-533 SDRAM, the $1148 ThinkCentre A51 earned a score of 79 on our WorldBench 5 benchmark test--hardly blistering, but comparable to the performance of other systems running the same CPU. It's certainly fast enough to handle most mainstream business applications. Not surprisingly, frame rate scores on our Return to Castle Wolfenstein and Unreal Tournament games were very low, and the integrated Intel 915GV graphics produced uncomfortably choppy game play.

The unit offers most of the connectivity options of a larger PC: two USB ports, a microphone jack, and a headset jack appear on the front of the case, and two more USB ports plus ethernet, parallel, serial, and PS2 ports sit on the back.

There's no room inside the A51 for a second hard drive, so if an 80GB drive (the size that came on our system) doesn't meet your needs, you should specify a larger drive at the outset. The case comes with one open PCI slot, one open RAM slot, and no room for an additional optical drive. But you'll find that working on the A51 is refreshingly easy: Just push two buttons on the side of the case and the sides swing open, offering unhindered access to important areas of the interior. Shutting the case posed a bit of a challenge: We had to rearrange the bundled cables several times before the case would completely close.

The lightweight mouse had a flimsy feel, but the simple keyboard offered good key action and included an unusual extra: a built-in fingerprint scanner for security.

The minimal documentation accompanying the A51 consisted of a basic printed user manual and a more detailed manual on CD; there was no setup guide or poster. But setting up this system is pretty easy--you just plug the power, keyboard, and mouse cables into clearly marked ports on the back of the system.

Upshot: This well-designed office PC occupies little space and is easy to upgrade (in limited ways) to extend its useful life.