Corsair AX1200 1200W Power Supply Review

Introduction

Six years ago, loading a true enthusiast machine down with all the hardware you could muster meant that you were pulling no more than 600W-700W, and finding a power supply to handle that kind of load was nearly impossible. Since then we've seen a huge change in the hardware that enthusiasts utilize in their rigs. SLI brought about multi-GPU systems that required more power than ever.

We've seen a switch from using a single desktop processor overclocked to the max to dual processors with multiple cores...still overclocked to the max. Let's not even get into everything else that has evolved inside the computer. All of this is great, if you have the power to feed all of it. These days you'll need a minimum of 1000W to power a high end enthusiast machine - maybe even more.

While you have your selection of vendors for motherboards, memory, storage, and more, finding a power supply to fit the bill of such a machine produces few options. The last 12-18 months have brought some more selections, such as the Corsair Professional Series AX1200 that we are taking a look at today. The AX1200 is Corsair's flagship power supply. It is the biggest, meanest beast that they offer.

This PSU boasts an 80Plus Gold rating, has enough connections and power available to run two or three "normal" computers, and has a whole lot of other features to go with it. What matters most of course, is how the AX1200 performs. Nobody wants their rig shutting down in the middle of intensive use when it is needed most. Keep reading to find out all about the Corsair AX1200 and how it performs.

Specifications, Availability and Pricing

One of the first things that you'll notice about the Corsair AX1200 is that it is actually rated for a little bit more than the 1200W that is labelled on the box. It is actually capable of 1204.8W. This is because of the massive 100.4W single 12V rail in the AX1200. Corsair makes sure the 3.3V and 5V rails are beefy as well, with both of them capable of pushing 30A each.



Corsair doesn't skimp on any of the features with the AX1200. It has everything you can find in a power supply. All protections available are included in the AX1200. The power supply is also fully modular, including the 20+4 pin Main connector. A majority of the modular cables are flat ribbon cables. For the few that aren't, they are sleeved. The AX1200 is also rated for 100% continuous output at 50C while still maintaining high enough efficiency to earn it the 80Plus Gold certification.

As would be expected from Corsair, the AX1200 is available just about everywhere. The AX1200 comes with an MSRP of $299.99, but can be had for as low as $279.99 if you do some very quick searching. That's quite a hefty chunk of change to be dropping on a power supply, but it is in fact one of the most important components of your computer. Corsair obviously thinks the same way we do about this and backs the AX1200 with an impressive 7-year warranty.

The Packaging

Our first look at the packaging shows a huge box. We've seen microwave ovens come in smaller boxes, but the AX1200 comes with a whole lot of power, cables and connectors, so it warrants the size. Surprising there's no marketing on the front of the box. It's kept simple. There is the model number and that's about it.



Checking the back of the box, we find that they have crammed all of the marketing information here. It almost reads like a white paper. There is a good list of connector availability, although it does lack cable lengths to go with it.



The sides of the box are just like the font, devoid of anything useful about the power supply. Both of them are the same.



Moving to the bottom, we finally find a little bit more useful information here. There is the warranty logo that lets us know that the power supply has a 7 year warranty and the 80Plus Gold logo telling us that this monster has great efficiency. Surprisingly, Corsair hasn't chosen to display the CrossfireX or SLI logo's on the box, despite it being certified for both.

Inside the Box

Let's move on to the goods shall we. Inside the box we find this is how things are packed. The AX1200 is well protected. All of the modular cables are contained in the bag on the right. It looks large enough to even accommodate the needs of Paris Hilton.



The power supply itself is also housed in its own felt cozy, protecting it from scratches during shipping.



On the top of the AX1200 is the I/O specification label and serial number for the power supply.



Both of the sides of the AX1200 are identical and keep it simple. There is simply the Corsair and AX1200 logos displayed here.



Taking a look at the back of the power supply, we find the honeycomb mesh grill to vent hot air out the back. It is only obstructed by the AC input and the very large toggle On/Off switch in the back.



Moving to the front of the AX1200, we see the 15 different connections for all of the modular cables. These should serve up all the connections you need in just about any combination of cables you can come up with.



Cooling this monstrosity is a 140mm fan with wire grill to keep airflow restrictions to a minimum.



Dumping out the bag of modular cables, we see that there is plenty to go around. In total, there are 19 cables. Not all can be utilized at once, but this adds a little more flexibility to tailor the cabling to your specific needs. Note that all of the "heavy duty" cables are sleeved. These are the Main, PCIE, and EPS12V cables. All of the peripheral cables are of the ribbon type.



Also included in the box is the user manual, power cable, cable ties, mounting screws, and a case badge.

Cabling Arrangement & A Look Inside

Cabling Arrangement



Whew, that's quite the list of cables and connectors. As always, there is the 20+4 pin main connector. There are also two ATX 4+4/EPS12V cables for motherboards that require it. To power a trio of high end GPU's, there are six PCI-E cables of the 6+2 variety so that they can be used in whatever manner you want. For those that still need 4-pin Molex connectors, there are three cables each with four connectors on it to give you a total of 12 Molex connections. SATA cables come in two different lengths. There are two shorter SATA cables with two connections each. For the longer SATA cables, there are three cables each with four connectors. This gives you a total 16 SATA connections.

One thing that we are very happy to see is that Corsair has not included FDD connectors as part of the modular cables. In the rare event that you should need them, Corsair includes two 4-pin Molex to FDD connectors. It would be nice if we would see more power supplies come to the market like this.



The Corsair AX1200 has simple rail distribution with everything on a single 12V rail. Normally this is about all we have to say on single rail power supplies, but the AX1200 does bring up a concern for some. Since all the power is coming from the 12V rail, there is 100.4A of power here. That's a lot of juice and it can melt the cable sheathing on even some very thick wires. This isn't necessarily an issue, just something that some people will have issue with. We aren't worried about it here, though.


A Look Inside



Since everyone wants to see just how this bad boy is laid out on the inside, here is a look with the bottom taken off of the power supply. Everything is very neat and tidy, partially due to the 100% modular design and the lack of a large clump of cables terminating inside the power supply. Five different heatsinks adorn the back half of the power supply to help cool things down.



On the primary side of the power supply, we see that Corsair has chosen a pair of Nichicon capacitors. For those that don't know, Nichicon Corporation is a very large Japanese company known primarily for their high quality capacitors and was established in 1950.



Corsair chose to utilize Nippon Chemi-con caps where needed on the secondary side of the power supply, giving the AX1200 100% Japanese capacitor construction.



Rounding up our shots of the inside of the AX1200 is a shot of the exhaust fan. It is a 140mm Yate Loon fan, model D14BH-12.

Test Results & Final Thoughts

Test Results

Our load tests utilize a couple of FAST ATE active load testers and a variety of other equipment such as an oscilloscope, power conditioner, temperature probe and a power consumption meter. You can read more about our standard testing approach here.

The tests performed are based around six conceivable setups that are out there and progressively load down the PSU up to the power supply's limits or 1000W, whichever comes first. Since our test equipment's limits lower than that of the Corsair AX1200, we can only test it to 1000W.





Taking a look at the voltage results, we see some rather impressive results for quite a heavy load. The AX1200 manages to maintain regulation on the 3.3V rail within 2% during the tests up to 1000W. The 5V rail manages a little better and stays just within the 1% regulation range. The single 12V rail manages 2% voltage regulation as well. While we have seen better voltage regulation out of other power supplies in the past, we haven't seen anything better out of power supplies of this caliber.

Ripple on the 12V rail was spectacular throughout all of the tests. Little can be said here other than, "Wow!" There is less noise on the 12V rail under a 1000W load than you see out of most power supplies under a 200W load. The Corsair AX1200 delivers the cleanest DC output quality of any power supply that we've tested to date.

Even without taking into consideration the total power the Corsair AX1200 provides, the efficiency results of the power supply are great. Not only do they show the power supply is deserving of the 80Plus Gold rating, but it is well within the limits.

While we don't have the equipment to test the Corsair AX1200, there are several conclusions that it is safe to say about the AX1200. Given the results that are shown above, there is no reason that the Corsair AX1200 would have failed any of our tests. The results shown above are all well within specifications. If anything would have been different, the total line regulation on the 3.3V rail may have dropped down to 3% at worst.




Final Thoughts

It's safe to say that there are few who will need a power supply of such high output. There are just a few power supplies out there that will fit fulfill such a need. One thing is certain, however. With the change in the way enthusiasts build their computers and the components, the need is growing. It is great to see Corsair offer a product fulfill the needs of enthusiasts and to offer it with such high quality as well. The Corsair AX1200 excels at delivering lots of high quality power. Voltage and line regulations are great with efficiency numbers to match it. Bundled with the AX1200 are plenty of connectors and cables to get you going and keep you going in the future.

The only thing that most will have a problem with is the sticker shock from the $299.99 MSRP, but when you're building a computer that requires a power supply of this caliber, you're already expecting that. At least with that hearty investment comes a 7 year warranty which leaves you knowing the AX1200 will be there with you for years and years to come.