Corsair AX1200i 1200W review: a new benchmark in high-end PSUs

The first digitally controlled power supply for high-end desktop PCs



Today Corsair introduced the AX1200i power supply it had announced at Computex. This isn't just any power supply, it's the first PSU for high-end desktop PCs to use a digital controller. The DSP is supposed to ensure extremely high efficiency and very low ripple values. It also comes with interesting features such as the ability to monitor and adjust vital parts of the PSU with software.

Corsair AX1200i

Traditional power supplies have analogue components for regulating the voltages in order to keep the efficiency as high as possible. Corsair is the first to implement a DSP (digital signal processor) in a desktop PC power supply. Corsairs claims a DSP is faster and more accurate, which should results in extremely low ripple values. The manufacturer promises ripple values less than a third of the maximum ATX specifications (40 mVtt instead of 120 mVtt). ATX specs also indicate that voltages can deviate by a maximum of 5 percent, but Corsair has lowered that to 1.5 percent. Stable voltages makes a PC run more stable as well. The faster and more accurate working of the DSP along with the absence of various analogue components also lower the amount of energy consumed by the PSU itself. The AX1200i is 80 Plus Platinum certified, but Corsair claims that the power supply is more efficient than (almost) any existing 80 Plus Platinum models. We will put that claim to the test.

Corsair AX1200i
The DSP is located on an extra PCB on the side of the PSU

The Corsair AX1200i has a single 12V rail that can supply 100.4 ampere. That effectively means that the power supply can deliver its entire capacity on the 12V rail, if needed. For the 3.3 and 5 volt rails the limit is 30A. As expected it comes with modular cables, a total of 12 molex, 16 SATA and six 6/8 pin PEG connectors all of which are nicely sleeved. Corsair even includes a small case for storing the unused cables.

The PSU is semi-passive, as the 14 cm fan remains off until a load of about 375 watts. In practice that means it won't make a sound when you're on the Windows desktop, for example.

Corsair AX1200i
Components include Japanese conductors

Product discussed in this review

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Corsair AX1200i

1200 W, 93 %, 80 Plus Platinum, Modular, 100.4 A

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