Corsair AX1200i Power Supply Review

Corsair has a refresh today that talks to its high end line of high power PSUs. The AX1200i comes in touting "platinum" efficiency and "an unprecedented level of monitoring and performance customization." How does the AX1200i perform out-of-the-box and does it actually bring value at its huge price?

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Build Quality

As we already know from the product images and packaging the Corsair AX1200i features a single 140mm fan design. 140mm fans are in the same vein as 120mm fans in that they can provide for quiet cooling environments due to the ability to move a larger volume of air at slower speeds than a smaller diameter fan. The 140mm fan is the almost the largest diameter fan we are likely to see in ATX power supplies given the physical constraints of the form factor. While great for quiet computing environments, the key criteria in our evaluation is whether or not the cooling solution is sufficient; not necessarily its sound level or form factor.

External Build Quality

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The exterior of the Corsair AX1200i is very similar to the HX850 Gold and HX1050 we recently reviewed. The external build quality of this fully modular unit is excellent as we have come to expect from Corsair. The modular interface on this unit is not "sort of" color coded as before but rather the connectors are numbered and the groups are labeled. The unit is dominated by its overhead 140mm fan, while the rear is perforated for good airflow. The black finish of this unit is a textured black finish exactly as we saw with the HX1050 and the actual finish is well done once more.

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The Corsair AX1200i itself is ~7 7/8 inches long while the modular cables provide a serviceable length of ~16 ~25 inches to the first or only connector. The sleeving is a combination of the flat FlexForce style and standard sleeving which is generally complete and well secured.

Internal Build Quality

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Once we open the AX1200i we see a general organization and arrangement that looks very much like what we saw from the previous AX1200. There are significant differences today as the PFC/PWM controller and supervisor IC has been replaced by a digital signal processor (DSP). Otherwise, the design of this is like many modern units with a resonant LLC primary and a synchronous rectification secondary paired with DC-DC VRM’s for the minor rails. We also see that the fan is once more the same Yate Loon fan that we saw in the AX1200 and it is rated at 0.7A at 12v. This fan is paired with four rather small heatsinks and the overall layout looks very clean and tidy including the soldering on the back of the PCB. A big hit to this is the fact that the fan lead is secured with electrical tape and hot glue in an otherwise high-end power supply. For the cost of this unit and otherwise professional construction, it would seem like this kind of patch job should not have been allowed out the door. Unless of course this is how the unit is supposed to be constructed, in which case that is even worse for a high-end unit such as this.

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As we look to the "primary side," we see that the filtering begins with the can (EMI line filter) on the housing and continues along the back edge of the PCB. In the midst of this we see the bridge rectifiers sandwiching a heatsink. The primary side power components are bolted to the heatsinks we find sandwiched between the coils and capacitors. On the outside edge of the PCB next to the power components for the primary side we find the DSP on the add-in PCB. The capacitors used for the PFC stage here are a bit different from what we saw with the AX1200 as today we find a pair of Panasonic’s rated at 450v 470uF 105C instead of the previous Nichicon's rated at 420v 470uF 105C. While not part of the primary side, one of the DC-DC VRM’s (5v) is situated very close to these primary components.

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Moving to the secondary, we see the transformers responsible for the 12v output in a similar arrangement as before with the AX1200. Beyond that on the side opposite the DSP PCB, we see the +5vsb as well as the other DC-DC VRM (3.3v). The modular interface is once more very clean and is attached to the 12v output wires which run back to the power components. The front side of the modular interface is generally very clean, but it is rather crowded. We also see here that there are a few standard Nippon Chemi-con capacitors in an area where these will get zero airflow, it would be much better to see solid capacitors in this area, and some Sanyo solid capacitors, the better solution. The capacitor selection in general is interesting with FPCAP providing what appears to be the majority of the solid capacitors on the secondary and Nippon Chemi-con providing the majority of the standard electrolytics.

Build Quality Summary

The overall build quality of the unit is excellent but not without a few caveats. First off, the exterior is once more like we have seen from recent Corsair units. Barring personal taste on the styling cues, the actual construction is high quality. When we move to the interior, things are generally excellent still, but the first thing we see, the hot glue and electrical tape securing the lead for the fan, is not exactly the number one thing you want to see in such a high-end unit. Moving on, that fan is a Yate Loon fan which is also not generally what you want to see in a real high-end unit and generally this fan has not been the quietest when we have seen it before. The actual integration otherwise is excellent with outstanding soldering and a clean layout that should help with airflow. The capacitor selection is high quality with FPCAP, Nippon Chemi-con, Sanyo, and Panasonic providing capacitors for the unit. The last thing of note is the DSP which Corsair is trumpeting so much. If the change to DSP control makes this unit absolutely outstanding in our performance metric than this expensive, currently, change is certainly a step in the right direction. However, if it doesn’t it is just an expense for no reason and really isn’t a high point of the unit’s construction as it has been trumpeted. That said; let’s go see how this unit performs now.