Silence your PC

Posted at: Friday 7th October 2005 by James Morris

A powerful PC doesn't necessarily have to sound like a jet engine. James Morris investigates how to make a high-end PC more acoustically demure

It's also worth noting at this point that our chosen motherboard had a fanless design, but active Northbridge cooling often involves some of the smallest, fastest-revving fans in your entire system. Typically, these can be as small as 40mm and may run at over 7,000rpm. We didn't need to upgrade these on our test PC but, like small graphics card fans, they're likely to be a source of irritating noise. The size of the Northbridge and proximity to surrounding components can preclude adding fans much larger than those supplied with the motherboard, but water cooling would provide a very effective alternative, as would an effective passive Northbridge cooler, such as the Zalman NB47J Northbridge Heatsink (£6.50 from www.kustompcs.co.uk), as long as you don't plan on overclocking.

GPU cooling

Once you've sorted out your CPU cooler, the next part to replace is the GPU cooler. Ever since the GeForce FX 5800 Ultra amazed us with its impression of a vacuum cleaner, HSFs on Nvidia graphics cards haven't had the best reputation for being quiet. Plus, even though the latest Nvidia products rely on parallel processing more than brute clock speed, higher-end products such as the GeForce 6800 Ultra in our test rig still create enough noise to really irritate you.

Fortunately, as with CPU coolers, you can replace the stock cooler with a much quieter alternative. The master in this particular area is again Arctic Cooling, with its Silencer range. Its NV Silencer 5 (Rev 2) not only cools more effectively than the stock HSFs on Nvidia graphics cards, but also emits less than a third of the noise, measured in sones, according to Arctic Cooling. The NV Silencer 5 uses ceramic bearings, which are guaranteed for six years and are rated at 274,000 hours of usage at 30˚C. We installed one of these to see how it would improve our noise levels.

When it was idle, the PC was 3.4dBA quieter from the front, with most of the reduction in the range of 2-4KHz, and 4.5dBA from the side, showing that the GPU cooler was emitting noise through the chassis side vent. At £13.52 from www.overclock.co.uk, the NV Silencer 5 (Rev 2) - like the Freezer 7 - shows that Arctic Cooling can deliver better cooling and low noise levels in one high-value package.

If you aren't opting for a water-cooling setup, then this is an upgrade that's well worth the money if you want a peaceful PC, particularly when it's combined with a quiet CPU cooler.

Power rangers

After that, it's time to sort out your power supply. Your PSU is likely to have two 80mm fans, although some have only one. A PSU with a 120mm fan would seem like a decent option for low noise levels, but unfortunately, these come with more than one catch. For a start, most of these units aren't available with ratings much over 400W. Worst of all, though, they aren't actually a particularly great idea, as the fan blows air upwards, with no exhaust fan to push it out of the back of the unit. This is very inefficient, and results in having to run the fan faster than would be necessary with a direct air path. A more sophisticated temperature-controlled PSU would be quieter in practice, especially if it drives air straight across the hot components.