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Silencing the CPU and Motherboard

Although virtually inaudible at the start of the tests, the fast-spinning 5000rpm Akasa CPU fan was now perceptible thanks to the low noise properties of the two AcoustiFans and the Zalman PSU. What was needed was a slower spinning and therefore larger CPU fan design.

The Zalman CNPS7000A-ALCU ‘Super Flower’ cooler fits the bill perfectly. Costing £34.08, the Zalman CPU cooler features a low-noise 92mm fan that has been cleverly integrated into a part aluminium, part copper heatsink. Also included is a Fan Mate speed controller that can be used to adjust the rotational speed between 1350-2400rpm.

A slightly higher specified all-copper version is also available from QuietPC for £45.83, although this must be removed from the CPU before transporting the PC anywhere as it easily exceeds Intel's recommended maximum weight for a heatsink. Also, because of their size and mounting arrangement, the Super Flower coolers are not compatible with all Pentium 4 and Athlon XP motherboard designs. Athlon 64 users should have no problems though.

After visiting the manufacturer’s website for further details, I was slightly concerned to find our Leadtek motherboard was one of the incompatible designs. The layout of the board was such that the two rows of capacitors on either side of the CPU interfere with the retention clip on the heatsink.

All was not lost however. Reading on, it turned out that Zalman’s ‘solution’ is to saw off the two outer holes on the clip (which are required for mounting on Athlon 64 boards) and the heatsink could then be installed as normal (see photos). This actually turned out to be a pretty straightforward task but it’s a shame Zalman couldn’t have included a second retention clip specifically for the Athlon XP and Pentium 4, as I’m sure not everyone would be as willing as I was to take a hacksaw to such a nice looking cooler.

After that slight technical hitch, the rest of the installation was quite simple. You first have to attach two metal clip supports directly onto the four heatsink holes surrounding the CPU on the motherboard. These are fixed in place from the rear of the board using small bolts and washers, which means removing the board from the case first. It’s then just a matter of applying the supplied thermal paste over the CPU before screwing the heatsink clip onto the two supports.

Since I already had the board out of the case, I thought it would be a good idea to replace the tiny northbridge fan and heatsink at the same time. Costing £11.75, the Zalman ZM-NB32J motherboard heatsink supplied to us by QuietPC doesn’t need a separate fan as it has oversized heat fins. This effectively reduces what little motherboard noise there was to zero. A small tube of thermal compound is also included for optimum heat transfer.

Depending on your motherboard design, the ZM-NB32J has to be installed in one of two ways. If your existing heatsink is secured onto the motherboard using pushpins, then these can be removed and new ones used to mount the silent model. For motherboards that don’t have holes for pushpins, the heatsink should be attached directly onto the northbridge using the supplied thermally-conductive epoxy glue.

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