Corsair AX750 80 Plus Gold: Putting Corsair's Best to the Test

With sales of around 150,000 PSUs a month, Corsair is one of the largest vendors for retail power supplies. Corsair got in earlier than most other lateral entrants like GeIL or A-DATA, and their time in the market has enabled them to gather a lot of experience even if they don't have their own factory. In recent times they've used CWT, Seasonic and Flextronics as their PSU ODMs.
A few weeks ago Corsair presented their newest PSUs, the AX series. The goal is to provide performance, quality and high efficiency, this is apparently the best power supply Corsair can offer at the moment. Today we'll look at the AX750; is the 80Plus Gold certificate justified? And what other useful features does it provide?
The AX750 and 850W models are based on a Seasonic design (X-400FL and/or X-760) with some modifications in the details. For example Corsair uses flat peripheral cables and offers a 7-year warranty. They don't have the PWM fan from the original (it's an Antec patent), but they use the same kind of fan regulation; we will see that later in our test. Interesting features include the fully modular cable management and a silent, semi-passive fan control. Here's a complete rundown of the features (and marketing material).
Corsair Professional Series Gold AX750 features:

• Supports the latest ATX12V v2.31 and EPS 2.92 standards and is backward compatible with ATX12V 2.2 and ATX12V 2.01 systems
• An ultra-quiet 120mm double ball-bearing fan delivers excellent airflow at an exceptionally low noise level by varying fan speed in response to temperature
• 80 Plus Gold certified to deliver at least 90% efficiency at 50% load
• Active Power Factor Correction (PFC) with PF value of 0.99
• Universal AC input from 90~264V
  • No more hassle of flipping that tiny red switch to select the voltage input!
• A dedicated single +12V rail offers maximum compatibility with the latest components
• Over-voltage and over-current protection, under-voltage protection, and short circuit protection provide maximum safety to your critical system components
• High-quality Japanese capacitors provide uncompromised performance and reliability
• Completely modular cable system allows you to use only the cables you need
  • Power supply upgrade and replacement is easy, as the cables only need to be disconnected at the power supply
• Low-profile, flat cable design reduces air friction and helps maximize airflow through your computer's chassis
• A seven year warranty and lifetime access to Corsair's legendary technical support and customer service
• Dimensions: 150mm(W) x 86mm(H) x 160mm(L)
• MTBF: 100,000 hours
• Safety Approvals: UL, CUL, CE, CB, FCC Class B, TÜV, CCC, C-tick

The 750W version is currently on sale for $150 online, with an additional $20 mail-in rebate. That's not too shabby, considering the older Seasonic X-750 still costs $170. However, we'll need to see if the quality of the AX750 matches the X-750 before we can determine if the reduced price makes this a better buy.