Corsair AX1200i PSU Review

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Even though the company started as a specialist manufacturer of RAM modules, Corsair has also been a major player in the PSU market for years. Nowadays the company offers a very wide range of power related products and their units are usually into every enthusiast's shortlist while browsing for high-end equipment. It would not be new if Corsair released just another high performance unit; however, today we are having a look at the brand new AX1200i, which is something more than a simple power supply. Bearing an 80Plus Platinum certification, boasting extreme performance figures and bringing the all-new Corsair Link DSP interface, Corsair obviously hopes for the AX1200i to become the favorite unit of hardcore enthusiasts. Does it have what it takes to entice the ludicrously demanding target group it aims at? We will find out in this review.

Manufacturer’s features and specifications

• Digital Signal Processor (DSP) for delivering extremely clean, efficient power with real-time adjustments
• Corsair Link™ Integration for monitoring and adjustment of performance, noise, and OCP settings
• Dedicated single +12V rail with user-configurable virtual "single rail" and "multi-rail" software modes
• An ultra-quiet, 140mm double ball-bearing fan delivers excellent airflow with exceptionally low noise levels by varying fan speed in response to temperature
• 80 PLUS Platinum certified, delivering up to 92% energy efficiency under real-world load conditions
• Active Power Factor Correction (PFC) with PF value of 0.99
• Universal AC input from 90~264V
• Over-voltage, under-voltage, over-current, and short circuit protection provide maximum safety for your critical system components
• Engineered to meet maximum power output at a server-grade 50°C temperature rating.
• Self-test switch to determine PSU functionality even before installation.
• High-quality capacitors provide uncompromised performance and reliability
• A seven year warranty and lifetime access to Corsair's legendary technical support and customer service
• Safety Approvals: cTUVus, CE, CB, FCC Class B, TÜV, CCC, C-tick

Read more: Corsair AX1200i PSU Review by VR-Zone.com

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Corsair supplies the brand new AX1200i in a large, dark cardboard box with a black/red color theme. There are no fancy colors and/or designs about the box, as Corsair went with a more "serious" look to attract the attention of professionals and workstation owners.



Inside the box, we found everything neatly packed and well secured. The power supply itself is wrapped inside both a nylon bag and a reusable synthetic pouch, as well as sandwiched between two Styrofoam pieces. It feels impossible to damage this product during transport.



The bundle which comes with the AX1200i is a little too basic for a unit with that kind of a price tag. Inside the box we only found a few cable ties, a case sticker, the Corsair Link interface connector, a black and white manual, the A/C power cable and four black screws.



Every cable of this power supply comes stored inside a basic nylon bag and, since this is a fully modular unit with a 1.2kW output, it is a big bag. Inside the bag we found six PCIe cables, two CPU 12V cables, the ATX cable, the Corsair Link cable, two Molex to Floppy disk adaptors, four cables for up to 16 total SATA connectors and three cables for up to 12 total Molex connectors. Note however that "only" 6 out of 7 Molex and SATA cables may be connected at the same time!

Those of you that are asking, "why make the ATX connector modular when you are going to use it no matter what?", the answer is simple. If the cables were to be hardwired, they would have to enter the unit and be soldered directly on the voltage supply lines. We will later see that by using a connector, Corsair moved the entire distribution of the power supply on the vertical PCB which is holding the connectors, increasing both the efficiency of the unit and the room available to install even more fancy features.

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Out of the box, the AX1200i will appear massive to a user who previously owned a typical ATX power supply. The 20cm long chassis is not overly long but it certainly is considerably longer than what the ATX design guides dictate, which might become an issue in smaller cases. Corsair sprayed the large chassis of the AX1200i with a matte black paint, much like with most of their power supplies.



Corsair usually places decorative stickers on the sides of their power supplies and the AX1200i is no exception, with stickers bearing the series and company logos glued on both sides of the unit, between an embossed lines design.



We found the sticker with the electrical specifications of the AX1200i on the top side of the chassis, covering about half of the unit's top side surface.



The rear side of the AX1200i is entirely perforated, allowing warm air to escape towards the rear side of the case. Besides the standard on/off switch and the typical A/C power plug, Corsair also placed a small sticker with the unit's logo on the rear side of the power supply.



No less than 17 connectors can be found at the front side of the unit, which seems excessive but was definitely expected from a fully modular supply with that kind of power output. Interestingly, the PCIe and CPU connectors share the same plugs, as well as the SATA and Molex connectors. There is also a self-test button with a green LED next to it, allowing the user to quickly diagnose if there are problems with their power system.

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A simple black Yate Loon 140mm fan is responsible for the cooling of the AX1200i; well, most of the time, since the unit is programmed to stop the fan entirely when it is not necessary. Ironically, the D14BH-12 is a high speed ball bearing fan, capable of bursting your ears at maximum speed, but with a very broad operating range as well.



The OEM behind the AX1200i is no other than Flextronics, a rather new company which was also responsible for the AX1200. It certainly is a non-standard design and the layout is clearly based on that of the original AX1200 but Flextronics performed significant improvements. Quality wise, the construction of the AX1200i is immaculate, with perfect soldering spots and a very clean layout.



Corsair is using an A/C plug transient filter which encloses all of the necessary components for a basic transient filter in a nice little package behind the A/C plug. However, the designer continued the filtering stage onto the main PCB, installing 2 Y capacitors, one X capacitors and two chokes more than what the ATX design guide dictates as the minimum recommended.



Surprisingly, the primary side capacitors are made by Panasonic HD, being the most expensive and high quality commercial capacitors we have seen inside a power supply up to this date. The two 450V/470μF capacitors have an operating temperature of up to 105°C.



The secondary side capacitors are made by Rubycon and Nippon Chemi-Con, making this power supply an all-Japanese affair. Plenty of solid state capacitors have been used as well. Corsair apparently needed more space as they installed several vertical PCBs, housing the VRMs, the DSP and Corsair Link circuits, as well as the protective equipment and sensors. Two large transformers are being used in the AX1200i, which are feeding the vertical block housing all of the unit's connectors and distribution circuits via a large metallic rail.



Corsair's Link software is perhaps the most innovative feature of this power supply and certainly a world's first when it comes to power monitoring. Certainly, other companies released units capable of displaying their output, voltages and other useful data; however, Corsair not only made the AX1200i capable of displaying every single piece of performance data there could be about a power supply but also gives end users the capability to program their own profiles, control the speed of the fan, even create virtual overcurrent protection (OCP) rails on specific parts of the equipment. And it does not even stop there as the Corsair Link software can monitor the temperatures of every system component with a sensor, the speed of every fan connected directly on system components and monitor/control other hardware utilizing the Corsair Link interface, such as their new Vengeance RAM modules. All of the aforementioned features can be performed by the Beta version of the software, with Corsair working hard to clear the bugs and add even more features.

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In order to provide you with the most professional and accurate reviews, we are using the following equipment to test the performance of power supplies:

Modified SECC steel case with thermal generation and control components installed
8 Vantek electronic loads, USB controlled
3KVA VARIAC
Extech 380803 TrueRMS Power Analyzer
USB Instruments Stingray Oscilloscope
SL-5868P digital sound level meter
CompuLAB interface
MyPClab thermal interface
Labjack U3-HV interface
Custom calibration box
Custom software
More information about our testing equipment and methodology can be found in this article - Behind the scenes: VR-Zone's PSU Testing Station Mark II by VR-Zone.com.





The electrical performance that the AX1200i displayed is setting new performance milestones, with virtually non-existent ripple and regulation below 1% on all of the voltage lines! The ripple on the 12V line barely exceeded 20mV under maximum load, figures which were unheard of to this date.



When it comes to electrical efficiency, the AX1200i easily conforms to the 80Plus Platinum certification, with the nominal load efficiency reaching up to 93.4% while the unit is powered from a 230VAC source. The AX1200i clearly prefers heavy loading rather than very low loading, as the power supply can maintain a very high efficiency up to maximum load but the efficiency drops sharply at 20% load and below.



The stock thermal control profile with which the unit comes pre-loaded with appears to be trying and balance the temperature of the unit between 40°C and 45°C with the lowest possible amount of noise, as the temperature remains virtually unchanged across a very wide load range. Although the algorithm allows the unit to heat up more while it is heavily loaded, the fan will spin notably faster in order to maintain the temperatures below 50°C.



As the AX1200i can fully stop its fan when it is not deemed necessary for it to spin, the stock thermal algorithm barely starts the fan while the unit is at 30% load and with an ambient temperature of 30°C. Due to the sophisticated control circuit and its great efficiency, the AX1200i runs incredibly silent, reaching up to 75% load before it even becomes clearly audible inside a silent room.

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Quality (30% of the total score)

Corsair has always been choosing the very best OEMs and most reliable parts for their performance power supplies; therefore, the surprising part is not that the AX1200i is an extremely high quality product but how Flextronics, a company which is relatively new among high performance designers and OEMs, is giving lessons on how a power supply is supposed to be made. Not only Corsair went with virtually the most reliable parts commercially available, the design is very clean and the quality of the assembly virtually spotless, which easily explains why Corsair covers the AX1200i with a 7 year long warranty.

Quality Score 10/10



Performance (40% of the total score)

Performance is what the AX1200i is all about. Aside from the great electrical efficiency, which was to be expected from an 80Plus Platinum certified power supply, the AX1200i delivered the very best electrical performance we have seen from any 1kW+ unit to this date. It also was the quietest 1kW+ unit we have ever tested, especially while it was mildly loaded, even though the operating temperatures were higher due to the very slow (or stopped) cooling fan. The best part however is that if the user does not like how the AX1200i behaves, he/she can tweak its features and then monitor its performance over the Corsair Link software.

Performance Score 10/10



Value (20% of the total score)

Unfortunately, value for money is not the strongest selling point of this product. Corsair's MSRP is 349.99 USD, making it one of the most expensive power supply units ever made. It can now be found retailing in Europe for about 290-320 EUR, therefore we believe that the street price will be lower than the MSRP price on every part of the world; still, the AX1200i is a massively expensive product, aiming towards only to those who are willing to break the bank just to buy the best possible power supply for their system. The only saving grace of the AX1200i when it comes to value is that the very long warranty increases the long-term value of the unit.

Value Score 8.0/10



Aesthetics (10% of the total score)

Aesthetics are a subjective matter but Corsair was very careful not to make this unit either overly fancy, which would deter most professionals and serious modders. The all-black design, no matter how much saturated it may be, visually matches the interior of almost any system. Other minor improvements, such as the side stickers and the chassis embossed designs, increase the aesthetic value of the AX1200i even further. Considering that is also is a fully modular design, we can hardly imagine that most enthusiasts will not like its understated, dark design.

Aesthetics Score 9.5/10

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