Verdict:

A practically perfect mid-range PSU - stable, efficient, quiet and modular.

The HX620W was launched at the tail end of 2006, and at that time, rated as being one of the most energy-efficient PSUs on the market. This no doubt contributed to readers voting for Corsair as 'Best PSU manufacturer of the year' in the 2007 Custom PC survey. After nearly 18 months, we were keen to see whether the rest of the PSU industry had managed to catch up with this well-designed PSU.

Although the HX620W is marketed as having three separate 12V rails, in reality, all are fed from the same circuit, so if any rails are starved of power, the circuit intelligently allocates more power (up to a maximum of 50A). This is a sensible compromise between having separate 12V rails and a single all-powerful rail, and also goes to show how silly the argument between manufacturers is about whether one or more rails is best. The motherboard and CPU connectors are powered by 12V1 and hard-wired into the HX620W, while 12V2 and 12V3 each power a modular 6+2-pin PCI-E socket and the five proprietary modular sockets for the Molex, S-ATA and floppy disk cables. The HX620W is very compact and is cooled by a pleasingly quiet, temperature-controlled 120mm fan.

The HX620W was easily able to output its full 620W without breaking a sweat, and proved to be an impressive 85 per cent efficient. This meant that it needed to draw just 728W from the mains to produce 620W.

Given the HX620W's very competitive price, quiet fan and modular cables, it's definitely worth checking out.

• Gaming Headsets - 26th September 2008
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• CPU water cooling - 17th June 2008

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