Corsair AX760i Power Supply Introduction

Last summer, Corsair impressed enthusiasts and experts alike with the release of the AΧ1200i. As it was stated in our review at the time, the highlight of the AX1200i was not the overall performance of the power supply, which was great nonetheless, but the DSP control instead, which DSP allowed users to monitor and control not only the power supply itself but other hardware as well. On the other hand however, the 1200W power supply certainly is exceedingly powerful for the vast majority of users, even for most hardcore gamers and overclockers. To that end, Corsair today announced the release of two smaller AXi models which should cover the majority of the enthusiast's market, the AX860i ($249.99) and the AX760i ($229.99). We put the AX760i to the test and today we bring you its thorough performance review.

The Corsair AX760i

Unlike the AX1200i, which was based on the AX1200, the AX760i is an entirely new platform and different than the previously released AX750, which AX750 the company also refreshed today with the release of the AX760, a version of the AX760i without the DSP control interface. The MSRP price of the AX760i is $229.99; not a low price for a unit with that kind of output but still a whopping $120 less than the massive AX1200i.

Corsair's fan logo

Still, the highlight of this power supply remains the DSP control which Corsair implements via their Corsair Link USB interface. The interface allows the end user to monitor the power supply's performance through a windows based application in real time. It also allows users to control certain features of the power supply, such as the behavior of its fan, the OCP protection levels, etc. The software also monitors temperatures and fan speeds of other devices it can recognize, such as the drives and the CPU, plus it offers the capability to create graphs, profiles and other fancy features which crazed tuners will surely appreciate. We should note that the software is compatible only with Windows 7, although we managed to get it working on Windows 8 as well, even though the HDD temperatures were reported incorrectly. Mac and Linux users however will not be able to use the software at all.

Corsair Link Software 

Manufacturer’s features

 

 

Manufacturer’s specifications

Warranty

Seven years

Dimension

150mm x 86mm x 160mm

Modular

Fully

Power

760 Watts

80 Plus

Platinum

ATX Connector

1

EPS Connector

2

PCI-E Connector

6

4 Pin Peripheral Connector

8

SATA Connector

12

Floppy Connector

2

MTBF

2,000,000 hours

 

Unboxing the Corsair AX760i

The box

The AX760i comes supplied inside a dark cardboard box with glossy red decoration. The walls of the box are very thick and the power supply is well secured between polyethylene foam slabs, as well as wrapped inside a reusable cloth pouch.

The box (Rear)

On the rear side of the packaging, Corsair fit the table with the electrical specifications of the AX760i, two graphs displaying the efficiency and the acoustics of the power supply, as well as a short description of the DSP/Corsair Link interface.

Bundled items

As far as extra's and fancy features are concerned, Corsair simply does not provide any. The purchaser of the AX760i will only find the necessary A/C power cable, a set of mounting screws, a few small cable ties and a case sticker. There is also a nylon bag which holds all of the unit's cables, since it’s a fully modular design. The Molex, Floppy and SATA cables are all-black, flat cables. Corsair used black sleeving on the rest of the cables but also used only black cables rather than color-coded, which definitely looks much better. Although the bundle is pretty standard for a power supply, we would have liked to see at least a few cable straps included with it. 

External Design of the AX760i

The Corsair AX760i PSU

As expected, the AX760i externally is exactly like a mini AX1200i. The length has been reduced to 160mm (6.3"), making the AX760i compatible with any ATX-compliant system. The power supply is black, with stickers attached to its sides and a decorative bottom part where the embossed ribs of the chassis are aligned with the fan's grill.

Side stickers

The side stickers of the AX760i are black but highly glossy as well. The company logo can be seen towards the left side of the sticker, although it is the model's logo which dominates.

Top side sticker

The sticker with the detailed electrical specifications of the AX760i has been placed on the top side of the chassis, where it will be visible through a windowed side panel only if the case has the PSU mounting area towards its bottom and the unit's fan is still facing downwards.

Rear Side

Despite the fact that this power supply can output "only" 64% of the power the AX1200i was capable of delivering, the rear side of the unit remains littered with connectors for the numerous modular cables. There are six connectors for PCIe devices and CPU EPS cables, a paired set of connectors for the 24-pin ATX cable, six connectors for the SATA/Molex device cables and a small connector for the Corsair Link USB interface. Finally, there is also a small self-test button with a LED next to it, for basic diagnosing purposes. The self-test switch runs a diagnostic check on all voltage lines, as well as the fan, indicating whether the unit operates properly. If all cables are installed in the aforementioned connectors, the AX760i provides a total of two EPS 12V connectors, six 6+2 pin PCIe connectors, eight Molex connectors and twelve SATA connectors; a very healthy number of connectors considering the output of this power supply. There are also two floppy disk adapters but which negate one Molex connector each if used.

Front Side

The front side of the AX760i is quite standard for a modern power supply, with most of it being perforated. The standard on/off switch and power plug receptacle are to be found, as well as a small sticker with the unit's logo.

A look inside the AX760i

The cooling fan

It would appear that Yate Loon D14BH-12 fans are Corsair's favorite, as they can be found in most of their power supplies. The AX760i is no exception. The ball bearing fan has a maximum speed of 2800RPM, which is unlikely to ever reach since, as you will read in the following pages, the thermal control circuit will not even turn on the fan while the unit is lightly  loaded. A simple ambient temperature probe has been placed next to the fan's engine, monitoring the intake (ambient) air temperature.

Inside the Corsair AX760i unit

It appears that the AX760i is a mini AX1200i not only externally but internally as well. Corsair seems to have ditched the Seasonic design they have been using for the AX750 and went with a Flextronics design for their new AX760i units. We are not currently aware if the plain AX760 is based on a Flextronics design as well or if Corsair is still using a Seasonic design for that. Apparently, the AX1200i must have been a great success for Corsair to approach Flextronics again for their smaller units. Flextronics did not let Corsair down either, as the AX760i is every bit as well made as the larger AX1200i, without any structural flaws and with excellent soldering points.

The filtering stage

The AX760i is narrower than the AX1200i and so Corsair had to ditch the A/C receptacle EMI filter, as that would block the installation of other components. Nevertheless, the filtering stage of the AX760i is excellent, with six Y capacitors, two X type capacitors, two chokes and a MOV.

Primary side

We found the bridge rectifier mounted on its own, fairly large dedicated heatsink. The heatsink is not large because the transistor is inefficient but because Corsair has this unit operating without any active cooling at low loads. Next to the bridge rectifier, the APFC circuit starts with a massive filtering coil and a 420V/560uF 105°C capacitor from Panasonic, with the diode and transistors on their own dedicated heatsink. The transistors forming the primary side of the LLC resonant converter have been placed on another heatsink, all the way to the other side of the main board.

Secondary side

The secondary side rectifier (LLC type) has been placed on a vertical board, ending to a thick metallic bar which distributes the 12V line around to the other PCBs and sensing circuits, while it also serves as a basic heatsink. The 5V DC to DC conversion circuit can be seen on a vertical PCB to the left side of the rectifier and the 3.3V DC to DC conversion circuit on a separate vertical PCB to the right side of the rectifier. The secondary capacitors are a mix of Rubycon and Nippon Chemi-Con products. Most of the power distribution takes place directly on the PCB holding the modular connectors, which thick metallic rails transferring the large lines about the plugs.

Daughterboards

Test Setup

The load

In order to be able to effectively and efficiently test any computer power supply unit, we developed and constructed our own proprietary testing station. Our testing station consists of a number of power resistors and small capacitors, which in turn are connected to a RS485 electronic relay array which allow our load to be controlled through computer software alone.

USB interface and connection panel

When accuracy and speed are of critical importance, a simple multimeter or voltage meter is not sufficient for the task. To ensure the quality of our testing, an USB laboratory interface is being used to continuously monitor and record the readings of all voltage lines simultaneously. For ripple measurements, an oscilloscope is necessary and we chose the USB Instruments Stingray, the most widely used oscilloscope amongst low voltage PSU engineers and testers.

Measurement instruments

For accurate testing and repeatable results, a stable power input is also required. Thus, we are providing power to our test samples through a 3kVA VARIAC which allows us to control the input voltage of our test samples and also perform efficiency tests under both 110V AC and 230V AC input. A Lutron DW-6091 is also being used, monitoring the input voltage, real and apparent power, power factor and amperage.

The software

A power supply testing procedure would not be complete without thermal and acoustics tests. For our acoustics tests we are using a SL-5868P digital sound level meter, placed 1 meter away from the unit (DIN standard). Two PT100 sensors and their respective displays are being used to monitor the ambient temperature and the exhaust temperature of the unit.

Complete test setup during trial run

Testing results (Regulation & Ripple)





Much like its larger 1200W version, the electrical performance of the AX760i is astonishing. Voltage regulation is kept below 0.8% between 20% and 100% load, much lower than even Corsair's marketing claim of 1.5%. The voltage ripple filtering is outstanding as well, with the maximum voltage ripple being a mere 20mV on the 12V line at maximum load.

Testing results (Efficiency, Noise & Thermal)

 

The AX760i is an 80Plus Platinum certified power supply so we did expect a very high electrical efficiency. During our testing and at 50% load, the AX760i managed to reach 93.6% efficiency when powered by a 230V source and 92.8% efficiency when powered by an 110V source. The efficiency appears to be more stable when the unit is powered by a 230V source, holding at 92.4% and above across the entire load range. When powered by an 110V source, the efficiency drops at heavy loads but never goes below 91%.

 

Our noise level readings up to 30% load were lower than 20dB(A) and essentially superficial, since the fan of the AX760i starts only when the load is higher than about 35%. The pre-programmed fan profile is obviously optimized for quiet operation as the fan will spin very slowly, maintaining very low noise levels up to 80% load. Only at heavy loads will the fan spin fast enough to reach clearly audible levels from 3ft away.

 

As the fan of the AX760i does not spin at 20% load, the temperature reading at that point was essentially that of the ambient air at the front side of the power supply. Even when the fan does start, the temperature delta is very low albeit the fact that the fan speed is very slow. Apparently the very high efficiency of the AX760i does the trick and the power supply remains very cool without the need of strong active cooling.

Corsair AX760i Review Conclusion

Corsair's AX series is all about the greatest possible performance in order to please the most hardcore of technology enthusiasts. The AX760i is exactly the product for those who want to buy an AX1200i for its unbelievable electrical performance but do not really need that kind of power. The electrical performance of this power supply is ridiculously good, with a voltage regulation of less than 0.8% and a maximum voltage ripple of 20mV at maximum load. On the other hand, the great electrical efficiency and design of the AX760i allows it to operate very quietly, even entirely fanless at low loads, meaning that the fan of this power supply will be stopped while a gaming computer is idling or running simple desktop applications, allowing casual gamers and enthusiasts to work in an entirely quiet environment when they just want to browse the net or work with common desktop applications. It is very likely that the fan will never even start if the AX760i is used to power computers which are not heavily overclocked and use a single VGA card. For those who favor thermal performance over acoustics, remember that the DSP interface allows the user to program a custom cooling profile through Corsair's Link interface.

 

Corsair's Link is certainly an innovative feature, quite useful for adept users and experienced enthusiasts, which will certainly applause the ability to have full control over their hardware with a few mouse button clicks. In its current version, the Link offers virtually endless monitoring capabilities from all of the system's devices (CPU temperature, fan speeds, etc.), allows the user to tweak the cooling profiles of the power supply, even create virtual OCP rails on the connected equipment. Corsair currently offers more parts which support the Link interface, such as RAM modules which offer real-time monitoring of their temperature and activity through the same piece of software. In time we will likely see more devices with the ability to connect on the Link interface, giving enthusiasts more and more flexible control over their hardware components.

Filtering stage

Even though Flextronics is a new player in the retail market, we were impressed with their work on the AX1200i. Today, they impressed us once again as the AX760i is every bit as well made as the larger AX1200i, with an excellent design and assembly. Alongside the numerous protection circuits, Corsair also opted for the very best parts and components available for retail power supplies, making the AX760i virtually indestructible, which is no wonder why they decided to cover this product with a 7 year long warranty.

 The AX760i

It would appear that once again the only handicap of the AX760i is its retail price. With an MSRP of $229.99 the AX760i is $120 cheaper than the AX1200i, yet it still is considerably more expensive than any other power supply having a similar power output. The long warranty and extreme performance of the power supply do offset the high cost but it will still place the AX760i out of the budget of most potential buyers.

LR Recommended Award

Legit Bottom Line: Taking all of the above points into consideration, the overall performance of the AX760i is unbelievably good, making this power supply perhaps the best product in the 700W to 800W range that money can buy at this point of time. On the other hand however, the price tag is sure to burn a hole in your wallet, making the AX760i a product for those willing to pay the premium price for the best possible performance and features.