Verdict: Looks great, but it isn't suitable for overclocked CPUs.

The Cooler Master Mars is one of the most original-looking HSFs we've seen. Once again, Cooler Master has chosen an appropriate name, since the design of the Mars appears to have been based (albeit very loosely) on the Red Planet.

The Mars comprises a tiny copper contact plate from which heat is conducted via three heatpipes into a large nest of fins arranged in the shape of a sphere. Inside the sphere is a horizontally mounted 90mm blue LED fan, which is controlled via PWM, although it can also be manually set to spin at 1,800rpm or 3,000rpm. The position of the fan means that it pushes air down over the VRMs around the CPU socket, but also that the top half of the cooler receives no direct airflow.

The Mars is compatible with both Socket AM2 and LGA775 CPUs. However, as it screws through the motherboard, you'll have to take your PC apart to install it. The fan didn't spin up to full speed in either of our test PCs in PWM mode, which caused the Socket AM2 CPU to overheat and shut down. In high-speed mode, the fan is loud and the cooling ability poor - in both test PCs, the CPUs ran 10ûC hotter than they did with the reference HSFs.

There's no doubt that the Mars looks great, and the extra cooling it provides for the VRMs is very welcome, but its terrible cooling ability and loud fan (when not in PWM mode) mean that it's best left on the shelf.

• Cases - 21st November 2008
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