Corsair AX1200i Modular Digital Power Supply Review

Final Thoughts

Pricing

In the UK the Corsair AX1200i costs £250 while in the USA it retails for $340.

Conclusion

Corsair’s AX1200i is a premium power supply. To anyone who knows what a 1200W PSU typically costs the £250/$340 Corsair are charging is nothing short of eye-watering – you can get 1500/1600W 80 Plus Gold power supplies for less money than this. Of course that isn’t a useful or fair comparison for any purpose. The Corsair AX1200i power supply is meant to have all the bells and whistles, so let’s go through everything our review has shown.

On the performance side of things we can see the digital controls had a massive impact on voltage regulation. The stability at all different load scenarios was just remarkable, across many rails we saw the same voltage at 40% load as we did at 100% – that’s very impressive in itself and the fact that is replicated across all the rails shows us that the DSP does make a notable difference. In terms of efficiency we can see the AX1200i is based off a solid platform and meets the 80 Plus Platinum specification as we’d hope. While efficiency isn’t vital for power supply higher efficiency does tend to be an indirect proxy for better quality components and in the case of the AX1200i the quality is very high. In terms of PFC we saw the digital PFC controller working wonders, only at 20% load was the PFC a little low but at every other load scenario it was close to a perfect 1. Finally, on to noise and ripple suppression. The AX1200i again did well here with exceptional suppression of power noise and ripple on the 5 volt and 12 volt rails. The results for the 3.3 volt rail were a little disappointing but still miles inside ATX spec. I think the CrossLoad performance of the AX1200i is particularly telling, the results are almost identical to the typical load testing we did which shows the combination of high quality components and a DSP works wonders – achieving consistently high performance under a variety of conditions.

The impressiveness of the Corsair AX1200i doesn’t just stop after the innovative DSP is out of the way. The power supply itself has a whopping 7 year warranty – that really is impressive. Only a few other power supply vendors can match that – as far as I know EVGA offer a 10 year warranty on some units. The AX1200i also impresses with cables and its quality. All the cables are totally black, end to end, with full black cables and/or full black sleeving and heatshrink. The AX1200i also offers up a few value-added features such as the functionality of Corsair Link and the self-test button – something I really liked.

What is there to mark the AX1200i down on? Well only a few things in my opinion. Firstly, the noise/ripple suppression performance on the 3.3v rail as I already mentioned just didn’t seem up to the standard of the rest of the product. However, it is still well within ATX spec and competitive for a high-end unit. Secondly, the power supply could probably benefit from 2 more PCIe 6+2 pins. It has 6 which is enough for three graphics cards but the reality is 1200W is enough for four, particularly Nvidia’s GTX Titans which are very power efficient. Of course three AMD R9 290Xs would probably be enough to max out 1200W but offering another two connectors would be useful in my opinion. It is up to the end user to make the sensible choice of what 4 GPUs a 1200W PSU can support. Finally, the PSU is very long. At 200mm you’re going to have serious PSU compatibility issues in smaller cases. All those extra vertical PCBs and digital controls need space so make sure you have a case that is capable of homing this beast.

Pros

• High efficiency – meets 80 Plus Platinum
• Totally silent
• Amazing attention to detail on the cabling
• Test button
• Corsair Link support and includes all the cables at no extra cost
• 7 year warranty
• Class-leading build quality
• Excellent PFC performance

Cons

• Staggeringly expensive
• Could maybe use two more 6+2 pin PCIe connectors
• Very long at 200mm
• Slightly weaker than expected 3.3 volt noise/ripple suppression performance

“There are premium products and then there’s the Corsair AX1200i. This is a crazy-good power supply that ticks every box. It has bags of performance, it has the best build quality and attention to detail I have ever seen on a power supply, it is totally quiet, it has a 7 year warranty and it’s full of nifty features like a power supply test button, a fan that can turn off at low loads and Corsair Link support. This really is the ultimate power supply for an ultimate system. Just remember not to check your bank statement after you’ve bought it!”

Thank you to Corsair for providing this review sample.