Cooler Master eXtreme Power Plus is a 500 W power supply that is being sold for only USD 40 at (USD 30 after a USD 10 mail-in rebate). Can it really deliver its labeled power? Let’s see if this unit survives our tests.

We have already reviewed the 460 W model from this same series, which was not able to deliver its labeled power. So we were really curious about the 500 W version from this power supply.

You need to pay attention as Cooler Master has two power supply series with similar names. The eXtreme Power series is around for a while and the power supplies from this series are presumably manufactured by Seventeam. Units from eXtreme Power Plus are manufactured by AcBel Polytech. So even though the names of these series are similar, each series use a different internal design.

The reviewed model is also called RS-500-PCAR-A3. Two things immediately caught our attention. First, the fact there is no reference for “500 W” on the power supply. If you pay close attention to the label (Figures 1 and 13) you will see that the number “500” printed on the upper right corner doesn’t have the letter “W” after it. This is usually a trick done by manufacturers to protect themselves against potential lawsuits (e.g., “we didn’t say this was a 500 W power supply; 500 is the model number;” a good example is the AcBel iPower 660 power supply we reviewed, which isn’t a 660 W model – hey, wait a minute… eXtreme Power Plus 500 W is also manufactured by AcBel… Hum…)

The second thing that we noticed on the label was the phrase “The +3.3 V & + 5 V & +12V1 & +12V2 combine power shall not exceed 431.5 W.” What? If you add this to the maximum power for -12 V and +5VSB we have a total of 450 W! So despite the product name, the label states in a format hard to be understood by the average user that this is in fact a 450 W power supply. As you know, we are completely against this kind of trick used by some manufacturers, and we honestly think that companies like this should be sued, as they are clearly trying to induce consumers to error. Nevertheless, for now we have to give Cooler Master the benefit of the doubt; let’s see during our load tests what is the real maximum power this unit can deliver.

Cooler Master eXtreme Power Plus 500 WFigure 1: Cooler Master eXtreme Power Plus 500 W (RS-500-PCAR-A3) power supply.

Cooler Master eXtreme Power Plus 500 WFigure 2: Cooler Master eXtreme Power Plus 500 W (RS-500-PCAR-A3) power supply.

Cooler Master eXtreme Power Plus 500 W is a small power supply (5 ½” or 14 cm deep) and doesn’t have active PFC.

The main motherboard cable uses a 20/24-pin connector, being the only one protected by a nylon sleeving that comes from inside the power supply housing. It comes with two ATX12V connectors that together form an EPS12V plug.

The reviewed power supply comes with only four peripheral cables: one with one six-pin auxiliary power connector for video cards, two with two SATA power connectors and one standard peripheral power plug and one with three standard peripheral power connectors and one floppy disk drive power connector.

Only the ATX12V/EPS12V cable uses wires with the correct gauge (18 AWG). All other cables use thinner 20 AWG wires. The use of thinner wires usually make the voltage to drop at the power connectors when the power supply is fully loaded. This is where the manufacturer could cut some cost.

We could complain about the number of connectors available, but we think four SATA connectors is more than compatible with a USD 40 product. But for a 500 W product it could come with two cables for video cards instead of just one, but once again this is how the manufacturer was able to cut costs.

The distance between the power supply housing and the first connector on each cable is of 15 ¾” (40 cm), and the distance between each connector on cables that have more than one plug is of 4 ¾” (12 cm). The good exception is the ATX12V/EPS12V cable, which is 21 ¼” (54 cm) long.

Cooler Master eXtreme Power Plus 500 WFigure 3: Cables.

Now let’s take an in-depth look inside this power supply.

Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.