Power supplies at jonnyGURU.com are scored in four categories: performance, functionality, value and aesthetics. Each category has a different weight that effects the overall score.
Performance (40% of the final score) - The AX850 really performs well. Voltage regulation was good, efficiency was excellent, albiet not to Gold standards in my unit, the fan produced virtually no noise and, other than some funky waveforms coming from the +5VSB, ripple suppression was fantastic. 9.5.
Functionality (20% of the final score) - You can't knock a PSU for being FULLY modular at all. My compaint was the mix of flat with sleeved cables. Some people like the flat cables, while others like the sleeved cables. Something bothers me about the mixing of the two. The PSU is compact, so that's a plus and they include an on/off switch on the back, which is also a plus. I feel comfortable giving the unit a 9.5 here too.
Value (30% of the final score) - The AX850 typically sells for around $189.99. This is rather expensive for an 850W power supply. There are other 80 Plus Gold modular power supplies for less. That said, this PSU is not, by any means, a "cheap" power supply in build quality. I'm going to be fair here and give this PSU an 8 for value.
Aesthetics (10% of the final score) - This unit has very tame looks. It's a flat back finish with "Corsair AX850" stickers on each side. Nothing too flashy, but sometimes that's a good thing. I think the biggest aesthetic anomaly here is the hodge podge of cables. I'm going to give this unit an 9 for aesthetics.
When we put this all together, we get a total score of 9, and thus the unit gets a "jonnyGURU recommended".
Computer power supplies have come a long way in just the last couple of years. With the implementation of resonant mode topologies and DC to DC converters for non-primary DC output, we've seen efficiency increase more and more. The AX850 is an example of how to implement these features as effectively as possible by avoiding the high ripple typically associated with resonant mode topology and the poor voltage regulation typically associated with DC to DC converters under load. The cost is high, but you get what you pay for.
Efficiency just below 80 Plus Gold
Quiet, especially when the fan didn't spin at all!
Decent voltage regulation
Good ripple suppression
Nothing really bad to say here.
The price is high... but you get what you pay for!
Hodge podge of modular cables. Some sleeved... some flat.