We've reviewed several other SilenX products in the past, including some rather rubbish PSUs, which had a tendency to overheat and shut down when we tried to run them at 100 per cent load, so we weren't overly optimistic about how its range of fans would perform. However, SilenX got off to a good start by bundling both metal screws and rubber anti-vibration fasteners with all of its fans.

The IXP-54-09 and IXP-54-14 are both 80mm fans, rated to spin at 1,300 and 1,800rpm respectively. The -09 and -14 parts of the model numbers are derived from each fan's rated noise level, which is 9dBA and 14dBA respectively. These are both fairly bold claims, considering the ambient noise level in a typical domestic environment will average 30dBA during the day. That said, the measured noise level of the IXP-54-09 was below the ambient noise level of our test room (20.1dBA), although the IXP-54-14 averaged 27.2dBA and also produced an irritating buzz.

One reason that the IXP-54-09 is so quiet is that it barely moves any air. SilenX claims that it produces 18cfm, but we couldn't measure its airflow, as it was unable to complete our 'black sack' test. The IXP-54-14 is rated as being able to shift 28cfm, although in our test, it only produced 18cfm.

The 92mm models of the iXtrema Pro series are the IXP-64-11 and IXP-64-14, which spin at 1,400 and 1,700rpm respectively. As with the smaller iXtrema Pro fans, the last two numbers denote their rated noise level, which is 11dBA and 14dBA respectively.

SilenX claim that the IXP-64-11 can shift 28cfm of air, although we measured it
as moving just 6cfm. Its noise output was less than 20.1dBA, the ambient noise level of the test chamber. The IXP-64-14 claims to move 38cfm, although in our tests, it moved just 28cfm. Its noise output of 22.5dBA was good, despite being much higher than its rated output of 14dBA. However, the tone of noise produced by the IXP-64-14 is annoying, which makes it sound worse than the 22.5dBA measurement would suggest. Ultimately, there's little reason to buy either the IXP-64-11 or IXP-64-14, as neither model is capable of moving much air.

The two largest iXtrema Pro fans are both 120mm models. The IXP-74-11 spins at 1,200rpm and is claimed to produce 11dBA and 42cfm of airflow, while the IXP-74-14 spins at 1,500rpm and is claimed to produce 14dBA and 64cfm of airflow. These airflow claims were fairly accurate, as we measured the airflow of the IXP-74-11 at 40cfm, although it registered 25.2dBA in the listening room.

The IXP-74-14 pushed out an impressive 61cfm, but is much noisier, emitting a very noticeable 30.4dBA. In contrast to the other iXtrema Pro fans, neither the IXP-74-11 nor the IXP-74-14 is particularly quiet, and therefore, neither model is worth buying.

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• 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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• SilverStone Raven - Peripherals
• Raptor Gaming M3 Platinum - Peripherals
• Intel Core 2 Quad Q8200 - Processors
• ATI Radeon HD 4670 - Graphics cards
• DFI Lanparty JR P45-T2RS - Motherboards
• BFG GeForce GTX 260 OCX MaxCore - Graphics cards