Modern PC components require plenty of power, and the trend is being exacerbated by multicore CPUs, dual graphics cards and DirectX 10 GPUs. Despite this, the humble power supply is often overlooked and seen as a commodity, of which any one will do.
But, buying a poorly designed power supply can make your PC unstable, and you risk damaging your components by installing one. Like most products, you can’t tell whether you’re buying a good power supply simply by checking the label. Manufacturers often list the wattage in an extremely confusing manner, adding up the wattage over the primary rails (3.3V, 5V and 12V) and publishing the sum as the total power output.
But no power supply can simultaneously produce the maximum wattage on each rail, so this can give an overly generous impression of a power supply’s capabilities. Plus, scrutinising the label won’t tell you anything about how stable the power supply can keep the voltages. This is one of the most important factors when choosing a power supply.
Also consider which connectors you need. Modern motherboards need 24-pin ATX power connectors, while some new graphics cards need a 6-pin PCI-E connector. SATA connectors are useful if you have a new hard disk or optical drive, as they’re more convenient than any converters you may already have. Finally, some high-end motherboards use an 8-pin EPS12V connector rather than the more common 4-pin ATX12 socket. Here’s three of the best that have been used in various Labs rigs recently.FSP Blue Storm II AX500-A
FSP is one of the biggest names in power supplies, and many notebooks and PCs use the company’s PSUs. The Blue Storm II is rated at 500W and costs $129 from Nintek
. It has a pair of 12V rails capable of delivering 18A each. The first supplies power to the motherboard, Molex, SATA and one of the PCI-E plugs while the other delivers to the CPU and second PCI-E plug. There’s also a 30A 3.3V rail, a 30A 5V rail and a 2.5A 5VSB (standby) rail.
Cooled by a temperature controlled 120mm fan, the Blue Storm II is relatively quiet. The casing only rose by 2°C after running at full load for an hour. This is the result of an average efficiency of 76% at 50% load and an impressive 81% at full load. It means that relatively little energy is wasted (through inefficiency) as heat.
The Blue Storm II failed one stability test: the voltage on the 5V rail dropped to 4.63V (below the minimum acceptable limit of 4.75V as defined by the ATX specification) when drawing the full 30A from it. Even at 15.5A, we measured only 4.78V.
Overall, though, the FSP was one of the coolest and quietest power supplies tested, but the underpowered 5V rail could cause problems if your components need to draw lots of power from it.Thermaltake Tough Power 700W W010RB
The Tough Power is Thermaltake’s debut model in a new (and soon-to-be-released) series of high-end, modular power supplies that should scale all the way up to 1.2kW. The Tough Power here is rated at a “mere” 700W, though, and will be affordable at around $150 from PC Case Gear
. It has a few quirks, the first of which is that it sports three PCI-E plugs; one hardwired and two modular (they can be disconnected if not required). Plus, almost half of the 120mm air intake is blocked by a sheet of transparent plastic.
There are four 18A, 12V rails, one which powers the modular PCI-E plugs and CPU, the second powers the second CPU, the third the motherboard and hardwired PCI-E, and the fourth the remaining modular plugs. There’s also a 28A 3.3V rail, a 30A 5V rail, a 0.8A -12V rail and a 3A 5VSB rail.
The Tough Power passed most of the stability tests, but failed to deliver enough juice on the 5V rail at 75% and 100% loads, just like the FSP. It did, however, manage a stunning 83% efficiency. Plus, despite the air intake, it managed our hour-long stress test, albeit at the cost of an incredibly loud fan. If the noise doesn’t bother you, it’s well worth considering. Enermax Galaxy EGA1000EWL
This massive 1kW power supply is undoubtedly the king of PSUs. At $451 from Umart
, it will not only power a shed-load of high-end components, but will also empty your wallet.
It achieves its rating with no fewer than five 17A 12V rails, which have a combined output of 900W. The 3.3V and 5V rails are both rated at 30A, the -12V rail at 0.6A and the 5VSB rail at 6A.
There are four PCI-E plugs (plus ATI CrossFire certification), 19 Molex plugs, 18 SATA connectors, and even a new 2x2-pin RAM power cable for the next-generation 32-64GB systems. Two fans are needed for cooling: a 135mm unit and an 80mm unit. The only problem could be fitting it into your case; it’s a whopping 220mm deep.
We’d expect great performance, and the Galaxy passed every voltage stability test with ease. It was also one of the most efficient power supplies around, averaging 82%. For the ultimate PC, stuffed full of high-end components, the Enermax is ideal.