Introduction

We would like to thank Corsair for supplying the review sample.

At last year's Computex we had the chance to see the newly released Corsair AX650 which is the fourth member of Corsair's flagship series, Professional Gold. All AX units address the enthusiast users who don't have a problem to invest a significant amount on a PSU, but expect only the best performance out of it. According to all reviews around the globe, including our own review of the Corsair AX850, all AX units are top performers with state of the art characteristics and features that will cover even the most demanding users out there. Surely their prices are a bit stiff but at least you get what you pay for.

The AX650, like the AX750 and AX850 PSUs, is based on Seasonic's flagship platform which the Seasonic X series units also utilize. Briefly, the AX650 uses a fully modular cable design which as we see will dominate in the years to come, has 80 Plus Gold efficiency and features a dedicated single +12V rail. Also its compact dimensions render it compatible with all normal PC chassis and the exclusive use of Japan made caps along with the ball bearings fan ensure a long, trouble-free lifespan. On top of that Corsairs offers a seven year warranty to all AX units ensuring this way the long peace of mind of all future buyers. But enough with the long talk, let's skip to the main review and see what the AX650 really has to offer and how it stands against the competition.

Specifications

Efficiency is Gold and unfortunately the same goes for its price too. At $150 it's one of the most expensive 650W PSUs in the market. The PSU can deliver its full power even at 50°C ambient, the only protections missing are OPP (Over Power Protection) and the relatively rare OTP (Over Temperature Protection), the fan is equipped with ball bearings for extended lifespan and its footprint is small. Finally, someone surely cannot miss the seven year warranty that Corsair offers with this unit (and all AX PSUs as well). Such a long warranty period provides the ultimate peace of mind to the future buyer.


There is only one +12V rail which can deliver the unit's full power, something very convenient since all modern systems draw power mainly from this rail. The minor rails have more than satisfactory power and the 5VSB rail is strong enough with 3A max power.

Cables & Connectors, Power Distribution

The PSU utilizes a fully modular cabling design and all cables are fully sleeved, except the peripheral/SATA connectors which use ribbon cables. Unfortunately Corsair/Seasonic considered that two EPS connectors in a 650W PSU would be too much so they equipped the AX650 with only one EPS connector. However there are four PCIe connectors along with many SATA and peripheral connectors. Strangely enough the number of peripheral connectors is equal to the SATA ones and this is odd because less and less components nowadays use peripheral connectors. In general all cables are long enough and the distance among the connectors is adequate. Finally all connectors use 18AWG which is the recommended, by ATX spec, wire size.

Since this PSU features a single +12V rail we do not have anything to comment about its power distribution.

Packaging

The box that contains the unit is quite large, especially if we take into account the PSU's compact size. In general the package is similar to the ones of the other AX units. On the front we find an angled photo of the modular panel along with the model number of the PSU, in the bottom right corner. The small Gold efficiency badge along with the badge for the seven year warranty can be found right under the model description. If you want to learn more about the available cables/connectors and the unit's features and specifications then you should take a look at the rear side of the box. There you will find two interesting graphs, one for the output noise and one for the unit's efficiency. In the first of the afore-mentioned graphs we can see that the PSU goes fanless at low loads. Actually the fanless operation is more temperature related than load related, meaning that if the PSU is running cold at low ambient then it will operate in fanless mode even if the load is high. On the contrary if it is quite hot and the ambient is high then the fan will engage even at low loads (<130W). This is of course the best thing to do since following this pattern the components of the unit are not stressed by high operating temperatures.