The Spire Blackmoon 650W is a PSU that lends itself to systems for power-hungry desktop and mainstream gamers. It'll happily power a range of system components that include mid-range PCI-E graphics cards and SATA equipment and ships with two 12 volt rails as standard.

During all of our testing the Spire Blackmoon 650W achieved 100 per cent of the manufacturer's performance claims, based on real-world scenarios.

However the total efficiency for the Blackmoon lagged behind all the other low-end power supplies under test, including the Xigmatek NRP 600W and the Fractal Design Tesla 650W. It also failed to gain any ground in terms of standby efficiency, and was the lowest performer in its range.

Compounding this poor power performance, the PSU was the loudest product under test in terms of decibel noise when compared to similar power supplies like the SilverStone Strider Plus and the Corsair HX 650W.

The 120mm fan did do its job well, venting heat and keeping the computer cooler on the inside than the outside exhaust point, and the cables did not significantly heat up during the high load tests.

Under load, the tested rails were all comfortably within the ATX-specified tolerances, easily meeting the standard, and the Blackmoon produced an almost jitter free voltage readout at the 75 per cent load mark, creating a near flat line to indicate low electrical interference.

Spire blackmoon 650w

A robust and solid build does help boost our confidence in the Spire Blackmoon 650W and the addition of the blue illuminated translucent fan was a welcome design addition to the otherwise plain black chassis with the usual honeycomb exhaust grill.

Dimension-wise, it's a standard 140 x 85 x 150mm and is somewhat more meaty than similar units weighing in at 2.432kg.

The manufacturer's stated AC power input is 200-240V 50-60Hz 8A and the Blackmoon 650W comes with a total of 16 well selected fixed output connectors; 1x ATX 20/24-pin connector, 1x ATX 8-pin connector, 2x PCI Express 6/8-pin connectors, 4x SATA connectors, 6x 4-pin peripheral (MOLEX) connectors, and 2x floppy connectors.

Despite its SLI-ready capabilities this is really an entry-level PSU providing no modular plugs, and it lags the other PSUs in the test for efficiency and audible noise.

Follow TechRadar Reviews on Twitter: http://twitter.com/techradarreview