Verdict: Easy to mount, but it can't passively cool overclocked CPUs

Noctua's first two CPU HSFs have only just been released, but we were able to source samples of both for this test.

The Austrian-designed NH-U9 is sold without a fan but can be used with either an 80mm or 92mm fan. A copper base sits astride the CPU heatspreader, into which are driven eight heatpipes. The heatpipes then conduct heat up and away from the CPU into a mass of 38 aluminium fins, which have a combined surface area of more than 3,800cm2. The NH-U9 simply screws into the standard CPU mounting bracket found on all Athlon 64 motherboards; for Pentium 4 motherboards, though, you have to bolt on a proprietary backplate first, which requires the removal of the motherboard from the PC.

With no fan fitted, the NH-U9 couldn't prevent our Athlon 64 and Pentium 4 test CPUs from overheating and shutting down, but with a 92mm Akasa fan, it was more effective. It cooled the Athlon 64 to 10ûC below the reference AMD HSF, and the Pentium 4 to 8ûC below the reference Intel HSF.

Despite its huge dimensions, the NH-U9 isn't able to passively cool an overclocked and overvolted CPU, so you may as well buy a cheaper, simpler design such as the Arctic Cooling Freezer 64 Pro.

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