Cooler Master Masterwatt 650 PSU Review 3

Introduction & Closer Look

On the test bench today is a brand spanking new power supply from the innovative folks over at Cooler Master! This is the Cooler Master MasterWatt 650w power supply which features an 80PLUS Bronze efficiency rating with a semi-modular design and a semi-passive cooling system.

The MasterWatt 650w sits firmly in the center of the new trio of new power supplies from Cooler Master; with a 550w and 750w also available at launch (today for anyone wondering). Let’s take a look, shall we?…

So, starting with the packaging, the MasterWatt 650 comes in a primarily black box and if you ignore the bump in the left corner, it looks relatively nice.

Cooler Master Masterwatt 650 PSU Review 1

Included inside the box is a variety of cables to power various components of your system. These include a 24pin ATX motherboard power cable, a 4+4 pin 12v CPU cable, 4 x PCI-e 6+2pin GPU cables, 9 x SATA connectors, 3 x Molex power connections and a single 4 pin floppy cable. Plenty of options here for even the sweetest of SLI or CF enabled multi-GPU configurations; check power consumption of your graphics cards first.

Cooler Master Masterwatt 650 PSU Review 2

Cooler Master Masterwatt 650 PSU Review 7

Looking at the unit itself, this 650w power supply has a nice shiny subtle speckle thing going on over the chassis. This looks pretty classy and the glossy finish will be hit and miss for some depending on system configuration.

It is worth noting that this power supply is semi-modular as the 24pin ATX and 4+4pin 12V CPU are hardwired into the unit.

Cooler Master Masterwatt 650 PSU Review 3

To the rear, Cooler Master has gone with a honeycomb styled mesh grill to aid in pushing hot air out the rear of your system (depending on PSU placement in case of course). There is also a simple on and off switch present.

Cooler Master Masterwatt 650 PSU Review 4

The overall look of the MasterWatt 650 is nothing short of exemplary and looks to be a nice and short option for system builders demanding quality, but without dropping copious amounts of money on an over costed unit.

Cooler Master Masterwatt 650 PSU Review 5

Performance & Testing

Since we don’t currently have access to an ATE load tester, a multimeter is used to show each of the power supplies performance on the 3.3v, 5v, and 12v rails. Although we can’t do full load tests, we can provide relative information regarding variance and fluctuation of current and ripple on the rails which is integral and indicative of quality in a power supply.

To perform the above tests, the methodology will be as follows:

Intel Core i7 7700K @ 4.5GHz
ASUS Z270 Maximus IX APEX
Crucial (2x8gb) 16GB DDR4 Ballistix Elite 3000MHz
1 x 525GB Crucial MX300 SSD

Voltages will be monitored via a multi-meter and the AC power draw will be monitored via a power monitor when drawn from the wall. For the idle test, the system will be simply booted up and let to run into windows and after 5 minutes when the power draw has leveled out, the readings will be taken.

To load and apply power to the power supply, a combination of IBT and Furmark will be run to put as much strain on the power supply as possible. After 10 minutes the readings will be taken and to ensure maximum strain, the CPU will be overclocked to 4.5GHz. Depending on the power of the power supply, multiple graphics cards could be used in line with how comfortable I feel the power supply will cope with such load. In the case of this unit, the GTX 1060 doesn’t support SLI. We will endeavor to improve our testing methods throughout 2017.

ATX themselves specify that a fluctuation and variable of 5% is acceptable so to number crunch it means that:

3.3V = 3.135V – 3.465V is acceptable
5V = 4.75V – 5.25V is acceptable
12V = 11.4V – 12.6V is acceptable.

Any readings outside of these figures will be an automatic fail.

3.3V = 3.38V
5V = 5.09V
12V = 12.41V
3.3V = 3.28V
5V = 5.12V
12V = 12.2V

The MasterWatt 650 performs exceptionally well during the testing for the value offered and although only 80PLUS Bronze efficiency rated, it makes 0 difference here in our testing.


If you’re looking to pick up one of the new Cooler Master MasterWatt 650’s up at launch, you’re going to be looking at spending around £65 in the UK with no current US pricing currently available. This makes the MasterWatt 650 cheaper than the Corsair CX650 and their 550w modular version too!; making the MasterWatt a good priced option!

The overall design is pretty sweet and I’m a huge fan of the glossy finish; it’s sort of unique in the current market and instead of just adding RGB all over the place, they have actually modeled the unit well and make it look quite classy. The semi-passive fan is also a highlight on this unit and for the total power output available (650w), semi-modular design and costing only £65, Cooler Master have a clear contender for a true budget unit on their hands.

Performance is up to scratch and for the price, the unit punches above its weight. It’s easy to see that Cooler Master is trying to dominate the custom scene with their MasterMaker range of products and so far, their latest C700P Cosmos case has done the company much justice. The only niggle I could see in our testing was the 3.3v lane running a little high, albeit well within the standards required by ATX themselves.

If you’re in the market for a budget range power supply, want top quality without paying for silly gimmicks, then the MasterWatt 650 should certainly be on your list. For around £65 at launch in the UK, it may only be 80PLUS Bronze rated, but this isn’t an indicator of quality and the MasterWatt 650 wins this time around!

Big thanks to Cooler Master for sending a sample of the MasterWatt 650 in for review.


  • Performance
  • Design
  • Value



– Great price for such a good quality unit
– Styling is good with a glossy finish
– Semi-passive and semi-modular design works well
– Plenty of connectors available through 5 additional included modular cables


– None found at time of review

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