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

After our initial recording, we upgraded these fans with a pair of SilenX iXtrema 120mm quiet blue LED fans (£19.98 each from www.kustompcs.co.uk). Not only do these fans' ADDA Hypro oil recirculation bearings and fan-blade design provide a low 14dBA rating at 1,600rpm, but they also come with rubbery silicon composite mounts to reduce vibration. Even so, they shift 58cfm of air, so they provide better chassis cooling as well as lower noise.

That sinking feeling

Chassis fans aren't the worst culprits when it comes to noise though. That dubious accolade must be presented to stock CPU coolers. If you've bought a retail processor then you can at least be confident that the heatsink assembly supplied with it will provide enough cooling to keep the CPU running stably at the manufacturer's rated clock speed. However, you can't guarantee that it will be particularly quiet. Intel's reference heatsink is a case in point. It certainly isn't a shabby piece of kit when it comes to keeping an LGA775 Pentium 4e cool, but the fan has to spin really fast to do this.

Processor HSFs often come with small fans that have to be run ridiculously fast to keep the air flowing. These small, whiney fans are some of the worst culprits in creating PC noise, particularly if you're overclocking. This is why we next focused our attention on quieter CPU cooling. We went straight for the jugular and swapped the Intel stock cooler for an Arctic Cooling Freezer 7 (£19.73 from www.overclock.co.uk). The difference between the two became obvious as soon as the fans had settled down after we turned on the PC. The noise level dropped by a whopping 6.4dBA from the front, and 7dBA from the side. The Jeantech chassis we used has a considerable amount of air vents in the side, which explains the extra noise here too.

This is the kind of reduction that you'll definitely notice when you're carrying out everyday tasks on your PC, and it shows just how much of the extra side noise was caused by the Intel stock CPU cooling. Of all the methods that we tried, upgrading to a Freezer 7, which costs less than £20, has to be the most cost-effective way of keeping down noise levels. Not only that, but in our last CPU cooler Labs tests, we found that the Freezer 7 is also one of the most effective coolers around for LGA775 processors, lowering temperatures by 12˚C more than the reference cooler when the processor was under load.

As the CPU cooler is usually the noisiest element of your PC, it's the most important part to sort out first. Replacing your hard drive with a quieter model will make a difference, but you're hardly going to notice it if the CPU cooler is screaming like an angry banshee over the top of it. For this reason, you need to quieten your components in order of priority, starting with the noisiest.