We tested power supplies from ASUS as long ago as 2004. ASUS has forgotten this market since then or its PSUs just have not come our way. But today we are going to introduce to you three new PSUs from that brand: two mainstream 550W models and a top-end 750W one. The difference between them goes far beyond the numbers on the labels!
Click the following link for a description of our testing methodology and equipment and a brief explanation of what the specified and tested parameters of power supplies mean: X-bit Labs Presents: Power Supply Units Testing Methodology In-Depth. If you feel overwhelmed with the numbers and terms this article abounds in, check out an appropriate section of the mentioned article for explanation.
You can check out other PSU models we have tested in our labs in the Cooling/PSU section of our site.
ASUS A-55GA (550W)
The 550W A-55GA power supply is a medium-wattage model in ASUS’s product range.
It comes in a small blue-painted cardboard box. A brief specification is listed on the back of the box: the allowable loads and currents on every of the power rails. Running a little ahead, I want to note that a splittable 20+4-pin mainboard connector is listed among the PSU’s features but my sample had a monolithic 24-pin connector.
The PSU is designed in the standard form-factor with a length of 140 millimeters. There won’t be any installation problems even with very cramped system cases. There are no remarkable features in the appearance of the A-55GA except for the orange On/Off switch. Such a switch can be seen with many PSUs manufactured by AcBel Polytech.
One look inside the PSU is enough to identify it as an AcBel. The A-55GA is based on AcBel’s popular platform that is used in PSUs selling under AcBel’s own brand as well as in PSUs from other brands, e.g. Cooler Master. The platform is not very new but meets the basic requirements of today.
The PSU is based on an ML4800CP chip which is a controller of both active PFC and main regulator. The input circuitry looks odd but does not differ fundamentally from other PSUs. There are just two parallel-connected high-voltage capacitors instead of one, and an E-core choke (it looks like the PSU’s power transformer) of active PFC instead of a toroidal choke. The output circuitry follows the classic design with joint voltage regulation.
Capacitors from LTEC Ltd. are installed at the output.
I can find no fault with the assembly quality of this PSU. AcBel has always been good in this respect.