The small form factor business PC is Lenovo's domain, and the ThinkCentre A55 9640-A11 offers all the usual ThinkCentre features, but also comes with Windows Vista Basic (optional to upgrade). Like other Lenovo desktop systems, we were impressed by the thoughtful business orientated design, but weren't so happy with the less than stellar performance.

Unlike the ThinkCentre M55 9BM, which we looked at recently, the A55 9640-A11 uses an older Pentium D 935 3.2GHz CPU, rather than the faster and more efficient Core 2 Duo CPU. Also installed are 1GB of DDR2 667MHz RAM and an onboard Intel 946GZ graphics chip. For storage the ThinkCentre has an 80 SATA hard drive and a DVD re-writer.

With Windows Vista Basic Edition installed, we were able to run our new WorldBench 6 software. WorldBench 6 is a scripted application-based test, which measures the ability of any given system to run important and commonly used applications in the Windows Vista environment. In WorldBench 6 the A55 9640-A11 scored a total of 61. This score is not overly impressive when compared to Core 2 Duo-based systems. The total score was brought down by the lack of a graphics card in the DirectX tests, where this machine is not designed to excel. Unfortunately, individual test scores for multitasking and Firefox were also slower than other low frequency Core 2 Duo machines.

One area where the ThinkCentre managed to keep relatively on par with the more powerful machines we've tested was in the Microsoft Office tasks, which is probably the focus of this unit. Lower scores in the rendering, Photoshop and media encoding tests show that this system will struggle to perform CPU intensive tasks.

Despite its lower performance, the A55 is priced fairly and will appeal to a business IT department rather than the end-user, as Lenovo puts a lot of effort into making these systems easily serviceable. Apart from the compact design, which will suite cramped or limited working conditions, the small form factor case has been built for quick access. Two buttons on either side of the chassis release the main lid, which rolls back and out of the way on a set of hinges, revealing the motherboard and the full-size expansion slots (including one PCI slot and one PCIe 1x slot). Once this is removed, users can unlock the front part of the inner cage with two slider locking mechanisms. This whole section houses the hard drive, optical drive and the system fans and they all become easily accessible. Most importantly, all of this can be done in a matter of seconds without a single tool. On the front panel are two USB ports and audio ports (headphone and microphone), so quick access for USB keys and other devices is available, without having to mess around at the back of the unit.

The CPU and chipset are passively cooled with airflow being delivered from the two front mounted system fans. These twin fans are designed to work together to reduce overall spin-speed and subsequent noise. They draw air from the front of the case and blow it towards the rear where it can exit via a grill. Overall, we found the system to be fairly quiet during general operation.

On the rear port cluster are six more USB ports as well as two PS/2 ports for a keyboard and mouse, though Lenovo has supplied USB peripherals with this unit. Also available on the back panel are a parallel port and a serial port, and a gigabit Ethernet port. There's also another set of audio ports at the rear (speaker and line-in).