Reviews - Corsair AX1200 1200W
Sample Provided by: Corsair (By OklahomaWolf on Sat, Jun-05-2010)

Page 1 -

Good day to you, my good readers. As you can see by the picture above, I'm reviewing a house today. It's a rather nice house from outward appearances, adding up to 1200 square feet on each of its two main levels, and comes with three bedrooms and two and a half baths. It's located in a wonderful neighborhood, close to schools and shopp... wait... that's not a house, is it? Glasses... glasses... where are... ah, here we go.

Well, would you look at that. That's definitely not a house. It's just a power supply box the size of one. Corsair's sent me their latest and by far their greatest today in the 80 Plus Gold rated AX1200.

First things first. Let's examine the back of the box where all the marketing goodness is. Since this box is approximately the size of the John Hancock building in Chicago, there's no chance any of you will be able to make out that printing. So, I'll type it all out for you:

  • Unprecedented Power Protection.
    The AX1200 pushes the state of the art for reliable delivery of clean power under imperfect conditions. If you require mission-critical stability or you simply want one of the best power supplies available, the AX1200 is for you.
  • A True Modular Cabling System.
    With the AX1200, all cables detach from the power supply. During installation, this gives you the flexibility of using only the cables you need for a clean system build with optimal airflow. And, when it's time to replace or upgrade your power supply, it can be removed from your system without interfering with your cabling - the cables stay in place and connect to your new fully-modular Corsair power supply.
  • Incredible Efficiency.
    With 90% efficiency at 50% load, the AX1200 runs quieter, generates minimal excess heat, and saves you money every month. It's earned the 80 Plus Gold seal of approval, your guarantee that you're making the right choice for smart, efficient power delivery.
  • The Corsair Advantage
    With more than 15 years of building enthusiast-grade memory and components, we've earned a reputation for quality, compatibility, and performance. Need help? We're available by phone call, email, or web forum.
  • Learn more about the pioneering technology that goes into the Professional Series Gold AX1200 by reading our white paper at:

Oh, goody! A white paper! For electronics nuts like me, white papers are cool. Let me just go over to the link and see... huh. No white paper. Maybe they're still getting it ready. This is a brand new product, after all. Let me check my reviewer's guide and see if there are any clues in there. Interesting... the reviewer's guide says that this unit utilizes synchronous rectification on the outputs and ZVS/ZCS (zero voltage/zero current switching) on the primary side to help it attain its remarkable efficiency. Often, the letters ZVS and ZCS go together with LLC resonant topology, like we saw in the Seasonic X650 way back when. As you will recall, that unit was among the very first 80 Plus Gold units to market. It will be interesting to get this puppy apart to see how it's made.

Meantime, let's take another look at the above picture. There are pictures of the connectors along with a count of how many come with the unit, a simple load table, and a couple of graphs representing noise and efficiency. In the event you don't speak english, the marketing points I reprinted up there are also present in French, German, Spanish, and Italian.

What you're seeing right now is one of the two sides of the box. The opposing side looks exactly the same.

This side of the box right here has a few more marketing points, as well as a few fancy logos. One of these indicates that in buying this unit, you're getting a seven year warranty. Nice. Here are the extra marketing points:

  • Mission-Critical Stability
    Leading-edge technology ensures performance under adverse conditions.
  • Unprecedented Flexibility
    The 100% modular cabling system makes installation, customization and replacement easier than ever.
  • Industry-Leading Protection
    Backed by a seven year warranty and legendary Corsair support.

I hate to tell you this, Corsair, but that unprecedented flexibility? It's... uh... precedented. See here and here and here. In fact, it's so precedented that Ultra Products has the patent on the modular cabling. And maybe it's just me, but I was somewhat expecting a little blurb about the protection circuitry present inside the unit, rather than a comment about the warranty. At this power level, I like protection circuitry. That warranty is pretty cool though, one must admit.

Another side of the box, and some more marketing. Here you go:

  • Auto-switching circuitry provides universal AC input from 90V-264V
  • Supports ATX12V 2.3 and EPS12V 2.91 standards. Backwards compatible with ATX12V 2.2/2.01
  • Dimensions: 150mm x 86mm x 200mm

Time to open the box. Hooray! Ah, look... there's a phone book in there.

Interesting - this phone book appears to have instructions, tables, and a big list of - sigh - more marketing points. Oh, very well - I'll reprint them too.

  • It supports the latest ATX12V v2.31 and EPS 2.92 standards and is backward compatible with ATX12V 2.2 and ATX12V 2.01 systems.
    -Nothing new here - we already saw this on the side of the box. Next.
  • 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.
    -I hear some of you asking whether or not I plan to verify this claim. Well, not really. You see, when you load test something in my lab, you almost need hearing protection already from the other bajillion fans running at the same time. You could fire up a jet engine in there and I wouldn't hear it, let alone an "ultra-quiet" 140mm fan.
  • Up to 90% energy efficiency at real world load conditions means less heat generation and lower energy bills.
    -We'll see how accurate this claim is during the load testing, as usual.
  • 0.99 Active Power Factor Correction provides clean and reliable power.
    -Actually, it does more for the AC utility than it does for the output of a power supply. This is also the circuit responsible for that universal AC input the box spoke about.
  • Universal AC input from 90-264V. No more hassle of flipping that tiny red switch to select the voltage input!
    -See my comment above.
  • A dedicated single +12V rail offers maximum compatibility with the latest components.
    -It can, I will agree. However, I know of no units in this power range that hinder compatibility based on the number of 12V rails. A few early units did it wrong, but engineers quickly learned to do it right. I'll get more into this later.
  • Over-voltage and over-power protection, under-voltage protection, and short circuit protection provide maximum safety to your critical system components.
    -Ah, there's that blurb about protection circuitry I was looking for. No overtemp protection or overcurrent protection, it would seem.
  • High-quality Japanese capacitors provide maximum safety to your critical system components.
  • The completely modular cable system allows you to use only the cables you need. Power supply upgrade and replacement is easy, as the cables only need to be disconnected at the power supply.
    -I have to admit, I do like a completely modular unit. They're easier to take apart on page four of each review. And Corsair does make valid points here, as long as the cabling on this unit remains compatible with future units.
  • Low-profile, flat cable design reduces air friction and helps maximize airflow through your computer's chassis.
    -Corsair's approach here is reminiscent of Ultra's "FlexForce," where the modular cables are done up in black ribbon cable. Some people like this approach, others don't - mostly because you can't tell which wires are which. I happen to like the idea.
  • A Seven year warranty and lifetime access to Corsair's legendary technical support and customer service.

As you can see here, the box came packed with a power supply in its own velvet PSU cozy, a 14 gauge power cord, a bag of modular cables, the New York City yellow pag... er... manual, some zip ties, and a case badge.

Here's the power supply itself, done up in that matte black color I like so much.

Another angle. You can see the big round metallic sticker on the back that proclaims that the unit does make use of Ultra's patented modular cabling system.

The exhaust grille is nice and unrestricted with a nice solid feeling power switch next to the AC receptacle. No wimpy little toggle switch for this bad boy.

The label, done up in black, white, and gold looks rather tasteful to me.

Here's the fan for you. This unit is so big, it makes a 140mm wind machine look small, doesn't it?

Here's the label, and the load table printed on it. As you can see, there are some odd numbers there. This is not, in fact, a 1200W unit - it's a 1204.8W unit. Huh? Why the odd number, Corsair? The unit can't do another 0.2 watts or something? Ah well - I'll test it according to these numbers and see what happens.

I wanted to take a moment to comment on that single massive 100.4A 12V rail. I've been seeing a backlash against multiple 12V designs, and I feel some comment from me is timely; though I've written about this before. As of right now, this is the largest single 12V design I've tested, with the Silverstone Zeus ZM1200M coming in a close second and Ultra's X4 1200W unit coming in third. I have mixed feelings about this. One one hand, I know why the single 12V rail is there and how it came to be in the marketplace. But on the other hand, it makes me a mite nervous. 100.4A is an awful lot of current. You can melt the insulation on some seriously thick gauge wires with that, never mind the 18-16 gauge wires most power supplies this size use to connect to your computer parts. Direct short circuits shouldn't be too much a problem, but what if something doesn't fail in a direct short? What if something partially fails, starts drawing massive 12V current through three or four small wires, and yet doesn't overdraw that 100.4A rail? There is a risk factor here when you start getting 12V rails this huge, people, whether you're talking about a Corsair, Ultra, PC Power and Cooling, or any other company's single 12V design. It's still a reasonably minor risk on a well built unit like this, but a risk is present nonetheless. My rambling point is this - multiple 12V rails aren't the devil, folks, especially on units that can pull more power out of the wall than your toaster.

I rather prefer the way Silverstone did it on the 1200 watt Zeus, with a switch you could use to implement multiple 12V rail overcurrent protection as desired. Personally, I would make use of such a switch for anything that's really "mission critical," like a server stuck in the back of a closet somewhere that has to run unattended for years. Memory tells me that Silverstone shipped those units with them set to single 12V, for the enthusiasts who like the idea of a single 12V rail this size. If I were working for Corsair, I would consider adding just such a feature to future units of this size. We'll have to find out on page four whether or not this kind of thing could be implemented easily on this particular unit.

Oops... looks like when I had my glasses off I picked up my "old codger" hat by mistake instead of my "harmless eccentric" hat. That explains the itching and the desire to go yell at people to get off my lawn. If y'all would like to buy a single 12V @ 100.4A power supply, don't let me stop you.

Corsair AX1200

+3.3V +5V
-12V +5VSB
30A 30A 100.4A 0.8A 3.5A
Max Power 180W 1204.8W 9.6 17.5W

Here are the modular cables for you. Not all of them are done in flat black ribbon cabling - some are done in sleeved ribbon cabling.

Use approved AX1200 cables only. We'll have to take care in the future when it comes to Corsair's marketing of the full modularity... this seems to tell us that compatibility will be limited.

Type of connector: Corsair AX1200
ATX connector (600mm) 20+4 pin
4+4 pin EPS12V/ATX12V connector (610mm) 2
6+2 pin PCIe (610mm) 6
SATA (440mm+90mm+90mm+90mm) 12
SATA (400mm+90mm) 4
5.25" Drive (460mm+110mm+110mm+110mm) 12
5.25" - 3.5" Drive Adapter (100mm) 2
Unit Dimensions(L x W x H)
200mm x 150mm x 86mm

Once again, Corsair had decided to do away with those tiresome hardwired 3.5" drive connectors on this unit, instead throwing in a couple of adapters. This is something I would like to see more of from Corsair's competition.


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