Verdict: Great cooling for both Socket AM2 and LGA775 processors.

The BTF90 is the only ZEROtherm product that we've tested, and we were impressed by its clear manual and easy mounting mechanism.

Even more impressive is the near 100 per cent pure copper construction, although this means that it tips the scales at over 680g - over 30 per cent more than the maximum weight recommended by Intel and AMD. Heat is conducted up and away from the contact plate by eight copper heatpipes and into the densely packed copper fins, which in turn are cooled by a PWM-controlled 92mm fan. This spins at speeds between 750rpm and 2,500rpm. However, in our tests, it didn't spin up to full speed and was relatively quiet.

The Socket AM2 mounting mechanism is easy to fit, and can be mounted on motherboards with either vertically or horizontally orientated CPU sockets, and still point in the right direction (exhausting air out of the rear of the case). With PWM activated in the BIOS, the BTF90 cooled our test CPU to an icy 15ûC below the reference AMD HSF. You'll have to remove the motherboard from your case to mount the BTF90 on an LGA775 system but, thanks to the ingenious removable fan, it's much easier than many HSFs to mount. In PWM mode, the BTF90 cooled our test CPU to 6ûC below the reference Intel HSF.

The BTF90 is an excellent HSF for Socket AM2 CPUs, and it's good for LGA775 CPUs too, but the Scythe Infinity is quieter and slightly cheaper.

• Cases - 21st November 2008
• Motherboards - 24th October 2008
• Gaming Headsets - 26th September 2008
• Dream PCs - 24th September 2008
• Headphones - 12th September 2008
• Media PC components - 22nd August 2008
• PSUs - 14th July 2008

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