Corsair AX 1200w ATX PSU Review

Introduction & Specs

For many years Wattage has been the male penis extension. Whether it be in the form of insanely loud car audio systems that you need ear plugs to operate, heavily modified car engines being measured in KW on a rolling road, or that unnecessarily high output PC power supply you purchased for your 486 DX2.  Its always been about bragging and trying to go one better than your mates regardless of whether you actually need the power or not.

However, in the PSU scene at least, times are changing. Back in April graphics card manufacturer nVidia released it's eagerly anticipated GTX480 card on the world. With it came word that the card was capable of sapping up to 300w from the wall at full load. Considering that most of the industry had slowly been moving towards 'ECO Friendly' computing this complete change in direction has given PSU manufacturers viable reason to start producing 1kw+ models once more.

Corsair are one such manufacturer that has done exactly this. Up until recently the HX1000 stood at the top of their mantle, being one of the most respected high-output PSU's available. However, due mainly to its now slightly dated design the PSU has started loosing ground to newer modes that can easily better it in areas such as efficiency. Determined not to be left behind, Corsair went back to the drawing board with the intention of creating yet another PSU that would raise the bar once more. What we're looking at today is that very PSU. The Corsair Professional Series Gold AX1200. So let's start with the specs..

*  Supports the latest ATX12V v2.31 and EPS 2.92 standards and is backward compatible with ATX12V 2.2 and ATX12V 2.01 systems
* An ultra-quiet 140mm double ball-bearing fan delivers excellent airflow at an exceptionally low noise level by varying fan speed in response to temperature
* 80 Plus Gold certified to deliver at least 90% efficiency at 50% load
* Active Power Factor Correction (PFC) with PF value of 0.99
* Universal AC input from 90~264V
      o No more hassle of flipping that tiny red switch to select the voltage input!
* A dedicated single +12V rail offers maximum compatibility with the latest components
* Over-voltage and over-current protection, under-voltage protection, and short circuit protection provide maximum safety to your critical system components
* High-quality Japanese capacitors provide uncompromised performance and reliability
* Completely modular cable system allows you to use only the cables you need
      o Power supply upgrade and replacement is easy, as the cables only need to be disconnected at the power supply
* Low-profile, flat cable design reduces air friction and helps maximize airflow through your computer’s chassis
* A seven year warranty and lifetime access to Corsair’s legendary technical support and customer service
* Dimensions: 150mm(W) x 86mm(H) x 200mm(L)
* MTBF: 100,000 hours
* Safety Approvals: UL, CUL, CE, CB, FCC Class B, TÜV, CCC, C-tick

At first glance there's very little to separate the AX1200 from the barrage of other high-end PSU's that pass through OC3D's labs on a monthly basis. Sure you get a 'quiet' 140mm fan, Active PFC, Universal AC input, Jap caps, a handful of safety features and a single +12v rail. But we've seen all that before. However, what does set this unit apart from a lot of the others is Corsair's impressive seven year warranty (which we've tested ourselves a couple of times) and that shiny 80PLUS Gold certification. Corsair will also be quick to tell you that the AX was designed in-house from the ground up, how it has a server grade power train architecture (toot-toot!) and how their Zero Voltage/Current Switching technology has helped the unit to achieve over 90% efficiency at 50% load. For further info be sure to check out their blog.

To put the efficiency side of things into perspective. If you were to run the AX1200 alongside a standard 80% efficiency PSU at at full load there would be a 144w difference in the amount of power that the two draw from the mains. Basically enough power to run a small HTPC, Laptop, TV...or GTX260 for PhysX processing ;)

When it comes to the rail layout, impressive simply is not the word. Considering that the AX1200 is supposed to be a 1200w PSU, it already over-delivers on this rating on the +12v rail alone. 100.4A (1204.8W) on a single rail is pretty insane and would certainly put on an awesome fireworks show if the safety features weren't there to keep everything in check.

Of course, as soon as you start putting load on the +3.3/+5v rails it does eat into this output, and with 30A available to either of the rails a maximum of 180w can be deducted from the 1204w output of the 12v rail. Mind you, this is just theoretical though, because we're willing to bet that the AX1200's max output is a conservative claim. One that will be quickly surpassed when it comes to our testing.

But first let's move on and see what goodies Corsair have bundled in the box...