Introduction

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



Corsair’s top-of-the-line series, AXi, so far includes three members with 760 W, 860 W and 1200 W capacity. Ask us and Corsair should probably add a unit with less capacity to satisfy users who need a top-notch PSU for a small- or mid-level system, but they instead decided to break every barrier in terms of cost and technology to offer an incredibly strong unit that is also the first high capacity PSU to meet the tough 80 Plus Titanium certification. For all of you who aren't aware: It is much easier for a small PSU to achieve high efficiency at full load and below because energy losses increase exponentially as the load increases. The power losses a 1.5 kW monster will suffer at full load due to even the slightest bit of resistance in its circuits can easily prevent it from meeting these strict Titanium or Platinum requirements. However, such hurdles become easier to master with digital control, and not only in terms of efficiency, but also when it comes to voltage regulation and ripple suppression.

The AX1200i was already the best unit we have tested so far, registering exceptional performance in all areas, so the AX1500i has quite tough standards to meet and exceed. On paper, it does look as though Corsair and Flextronics managed to further improve the digital platform by squeezing even more performance out of it. Corsair speaks of up to 94% efficiency, which allows for 1500 watts of power with even 115 V (15 Amp) circuits. Such numbers are not to be taken lightly since a regular US outlet allows for up to about 1725 watts of power draw, which means that a 1.5 kW PSU should have no less than 87% efficiency at full load and under all conditions. Anything less would overload the circuit and trigger its breaker. The situation isn't as dire in the EU since 230 VAC has a typical (15 A) EU outlet deliver up to 3450 W of power.

The AX1500i features a fully modular cabling design and an FDB fan, and its digital circuits allow you to monitor and control various functions through the Corsair Link software. You can also exploit a semi-passive operation Corsair dubbed Zero RPM Fan mode with low and medium loads, which drastically reduces output noise. The single +12V rail can also easily be broken up into multiple +12V rails through the software, a safety measure many users will appreciate.

Specifications

As already mentioned in the prologue, this is the first PSU to meet the strict 80 Plus Titanium requirements which are even more demanding than the Platinum ones. The AX1500i can also deliver its full power at up to 50°C ambient, which is amazing given its 1.5 kW capacity. The PSU, oddly enough, lacks under-voltage and over-power protections if you go by its official specifications, but everything else, including OTP, is present. Note that OCP triggering points for the ten PCIe sockets can be set individually through the Corsair Link software.

A high-quality Fluid Dynamic Bearing fan equips the unit, which boosts reliability and restricts output noise.

Since this is a real powerhouse, its dimensions are pretty large, so you should check to see if your case can accommodate such a large PSU before buying it. Its price and warranty period are both on the high side.

The full 1.5 kW of power this unit can produce are delivered by the +12V rail alone, which translates into a crazily high 125 A at full load! At 180 W combined, the minor rails are very strong as well, and the 5VSB rail has enough juice to feed the most demanding peripheral devices.

Cables & Connectors, Power Distribution

Since it can deliver huge amounts of power, Corsair equipped it with numerous connectors and cables, and all of them are modular. Its owners will have two EPS and ten PCIe connectors at their disposal simultaneously. There are also twenty SATA and twelve peripheral connectors! This is the first time we have come across a unit with as many SATA connectors. Corsair also provides two cables to either connect the unit to a Corsair Link Commander or a USB header on the mainboard.

All cables are extremely long, which is sound since this is a PSU for a cave-sized full-tower case, and the distance between SATA connectors is good; however, we would like the peripheral connectors to be further apart from one another. The 24-pin ATX and all EPS and PCIe connectors use 16AWG gauges for lower voltage drops. All others utilize 18AWG wires.

Since this PSU features a single +12V rail, we do not have anything to comment on when it comes to its power distribution. You can set the OCP for each of the ten PCIe sockets through the provided software for some extra protection, though.

Packaging

The AX1500i is enormous, so its package is quite large. An photograph of the unit and the model number occupy the front. A series of icons describe the seven year warranty, its semi-passive fan mode, Corsair Link functionality, and 80 Plus Titanium certification. Since Titanium efficiency is noteworthy, Corsair should use a larger Titanium badge to draw more attention to the efficiency certification.


Only the model number is depicted on this side.


A multilingual compatibility list can be found here. The list also includes the unit's dimensions, so you can check to see whether your case can support the unit.


More information on the product and its features are given on the back of the box. Two graphs provide efficiency and fan-speed curves, and the power specifications table is near the bottom-right corner. Corsair also provides some information on Zero RPM Fan mode, which, with 25°C ambient, is active at up to 30% load. There is also a very brief introduction to the Corsair Link feature.

Contents

Inside the box, the unit is protected by sheets of packing foam and is stored in a luxury cloth bag with Corsair's logo on it. We didn't expect anything less with such an expensive high-end product.


A nylon pouch contains the many modular cables. The rest of the bundle includes several zip ties, a set of fixing bolts, a case badge, and a heavy duty C19 power cord (with a US-type plug for our sample).


There is also a user's manual, a warranty guide, and a green piece of paper to inform you that you must download the latest version of the Corsair Link software from Corsair's site.