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So we've just laid our hands upon the Corsair HX620W Power Supply. I comes to us in a nice, yet typical packaging. If you've ever bought a power supply before, then you'll know what I mean. A box with boasts of SLI and or CrossFire readiness, pictures of the connectors and parts included, and usually some of the power specifications.

And since power supplies are all about, well, power, those performance specifications are important.

Pretty standard voltage inputs and outputs. We can delve deeper into those figures a little later, but something of importance first. As it happens, Corsair also sells a 520W version of this supply. The only real difference being the color and output. Whereas our HX620W supply is red on black, the HX520W is yellow on black. There is also the difference in wattage which can be solely attributed to the +5V and +12V lines. Where the HX620W puts out 30 Amps of current at +5 Volts, the HX520W will only produce 24 Amps of juice on that same +5V line. As for the +12V rail, the HX620W will output up to 600 Watts across its 12V rails, and the HX520W only 580 Watts. But one thing that should be considered for every power supply out threre is the number of 12V rails. We can see that the HX620W has triple 12V rails, probably the bare minimum for any high performance power supply built today.

You might wonder why the wattage is such a strange number and why Corsair didn't start out with 700, 800, or 1000W PSUs.  Part of this is Corsair's marketing philosophy: they believe strongly in being very conservative in their ratings and overperforming compared to other similarly rated products.  So while some manufacturers are claiming to deliver 700W PSUs, their actual electronics are no different than those of conservatively rated power supplies like Enermax or Corsair PSUs in the 500-600W range.

As with any power supply on the market today, there are a host of other features to detail. I'll drift through some of these other performance aspects one by one.

99% Active Power Factor Correction is a means by which a power supply will regulate the input voltage and current demands. The Corsair HX620W supply boasts this 99% PFC spec, as PFC has quickly become an industry standard. All PFC does is augment the power being supplied to a device so there will be less power consumed overall.  Case in point: you have a grapics card that will draw 150 Watts at idle and 250 Watts at full load. Though the voltage demands of that card won't change, the current draw in Amps will. Active PFC will supply that device with the exact amount of power it is demanding, and will not consume un-necessary electricity. In fact, Active PFC power supplies have been legally legislated in Europe for the past couple of years, simply in the hopes that Active PFC driven computer will consume less power from the electrical grid.

Double foreward switching circuitry isn't particularlly important, except where it pertains to overall power consumption. Every electrical device will suffer some form of power loss due to electrical resistance in the form of heat. For our Corsair HX620W, it can maintain an 85% efficency rating during system idle of approximatlly 140 Watts of draw. This means only 15% of the electricity consumed will be lost due to resistance. But naturally, as you increase power demands by surfing the Interweb and encoding some MP3's, the power draw will rise. When we fire up some games and run our system to its absolute limits of 620 Watts draw, we see only a 73% efficency rating. Now if a PSU didn't have these switching circuits, then the power effeciency would be even lower. But all power supplies have this capabality is some form or another; and Corsairs looks to be quite effective and a little more effective than most in some cases.

Auto switching is simply a method by where an electrical device can automatically switch its voltage inputs between 110V (North America) and 220-240 Volts for many European and other worldwide locations.

Triple 12V Rails is pretty common for most power supplies, though I have seen (and touched) some power supplies that will claim to have up to five 12V rails. Spreading the load out over mutiple rails helps to reduce stress on SU components and to aide in the constant delivery of power to respective components. If one rail were to become over loaded, that impedence wouldn't affect devices connected to the other rails. And if that one loaded rail still needed more power, then the triple 12V rails could fore go independence and work togeather in power sharing.

And Over Current/Voltage Power Protection is quite simple. Over voltage and over current protection acts like a fuse or a circuit breaker. If a power spike should happen to pulse through your outlet, the Corsair HX620W will stop that surge in its tracks, hopefully, preventing any damage to the PSU. It can do this in one of three ways: a fuse, a current limiting diode, or a circuit breaker, but I am pretty certain that the HX620W uses a large current limiting resistor to prevent excess amperage from getting through. My suspicions were further confirmed when I peeked around inside of the Corsair HX620W power supply.

It may be wrapped up in some heat shrink tubing, but there is some silk screen lettering that says something to the measure of "Only replace with same part". My guess is that because of the robust nature of power supplies today, it is rare for them to fail, except in the case of power surges. If a power surge may occur and a users PSU goes dead, it's probably just this little over current/voltage protection that failed. Said user might send the supply in question back to Corsair and they might just replace the blown resistor. PSU as good as new.

Naturally, I had to do a bit of snooping around to determine what form of over power protection the HX620W has. It didn't take me long either. But I'll save that for the next page. We've touched on the finer performance aspects of the Corsair HX620W PSU, and now it's time to perform some power supply surgery. Our first area of interest will be the bundled extras.