There is no doubt that the AX1000 is one of the best 1 kW power supplies available on the market today. Its performance is excellent in all areas, including efficiency, load regulation, ripple suppression, hold-up time, and transient response. It also operates quietly, which is why it earned the Cybenetics LAMBDA-A badge. Extremely high efficiency levels from the platform keep thermal loads low, which keeps temperatures low without pushing the fan too hard. Speaking of the cooling fan, although I personally didn't encounter any problems with it in any of the AX1000 samples I evaluated, I would prefer a Corsair fan, either the NR135P or NR135L with a rifle bearing.

At $240, the AX1000 is expensive, but this is a high-end PSU of topnotch build quality, and the Seasonic Prime Ultra with similar specifications costs more even though its only advantage over the AX1000 is the longer warranty (twelve vs. ten years). That said, a ten-year warranty is already overkill for a power supply in my opinion.

There are only three downsides I was able to spot: The EPS cables use 18AWG gauges instead of thicker 16AWG gauges, which would allow for even lower voltage drops—thicker gauges would also offer extra safety in extreme scenarios where lots of amperes pass through a cable. Peripheral connectors, especially the 4-pin Molex ones, aren't far enough apart—too short at only 100 mm, 150 mm would be perfect. Finally, the OCP triggering points on the minor rails (5V and 3.3V) should be lower since there is no point for such high amperage on those rails anymore.

In closing, the AX1000 is a fine power supply. If you need such a powerful PSU, make sure to put it at the very top of your list of possible candidates.