Cooler Master’s previous GX line-up was a disaster for the brand when news went about how the unit failed under various load test, even I encountered the breakdown of the GX power supply before.
With the many negative feedback Cooler Master claimed to have improved the GX II line-up and I must admit that I was a bit reluctant to try it out but after having used it for quite a few months now, it really does look like the Cooler Master made improvements.
The GX II is a single rail PSU, delivering 60A over the 12V rails.
Fan grill picture, a MUST HAVE in a PSU review.
Sleeved cables, good looking. Seeing that the PSU is non-modular, black sleeves make it easier to “hide” the cables.
And besides all the usual connectors, The GX II 750w comes with a Nonstop USB Charger.
Here’s how it works.
More details at the official product page.
User Experience
I’ve tested it on full load with various overclocked components, in some occasions running the HD 7970 on full load 24/7. No issues with the power supply so far.
Until I acquire some load test devices [not cheap!], we’ll just stick to the basic / intermediate user experience test.
The Verdict
The GX II 750w retails at about RM 370, which is quite a good value but it does have some competition in the market as well.
The basic weight of the CM GX-650 is approx. 2.2 kg [shipping weight approx. 2.5 kg] and the overall size is about 150x143x86mm.
The technical data of the 650 Watt power supply can be checked at any time on the attached label. The Coolermaster GX-650 RS-650-ACAA-D3 provides following voltage levels and amperages: +3.3V 25A ; +5V 25A ; +12V 52A -12V 0.5A ; +5VSB 2.5A
All voltages could be tested on different loads also with external measurements very well and pointed to a good technical conversion of the switched power supply. The combined total output values should not exceed the following ratings: At +3.3V and +5.0V up to 150 Watt, +12V up to 624 Watt and total consumption of all power lines should not exceed 650 Watt [continuous operation according to manufacturer with maximum load and up to 780 Watt peek].
These are manufacturer values, which one should not exceed, to avoid overloading and too high heat development. Apropos overloading – of course the PSU offers also all kinds of short-circuit-, overcurrent-, output- and input power protection, [SCP, OVP, OPP, UVP, OTP] which was tested successfully in the test attempt. Nevertheless one should avoid any installation failures, because under certain conditions it is possible to destroy the PSU, or other parts of the PC [up to a fire by e.g. cable fire with loose or wrong connections].
Furthermore, the power supply has an dual-mode-active PFC [Power Factor Correction] for reduction of the reactive power, the EMV noise and improvement of the efficiency. Meanwhile at least the more inexpensive less efficient and bigger passive PFC [upstream throttle] is legally prescribed. So also here the company Cooler Master saved by no means and offers a power pack with 80PLUS BRONCE certification, which has a .90 PFC value.
Own measurements of the test system with ASRock 890GX Extreme3 motherboard, AMD Phenom II 710 X3 CPU, 4GB DDR3-1333 memory, hard disk and ATI Radeon HD4870 PCI-E 2.0 video card resulted in an idle value of 161 Watt and a maximum value with full system load of 238 Watt. Switched off in the S5 mode, the test system with the GX Bronze power supply needed max. 3 Watt. Above all the idle value of 161W with small load is thereby much higher than the value of previously tested Cooler Master Silent Pro M500 power supply of approx. 140 Watt with lower 500W total power and the tested Cooler Master Silent Pro Gold 1000W power supply with an consumption in idle of approx. 124 Watt in spite of higher 1000W total power. More power supply reviews will published here.
You can calculate the current consumption and cost of electricity easily: Interactive power consumption calculator
The MTBF [Mean Time Between Failures] of the power supply is according to the manufacturer with 40°C about 100,000 hours, which distinguishes finally the reliability of the power supply, this time between 2 possible errors is enormously good.
The 120mm fan reached thanks to temperature control an optimal adjustment of the volume for necessary cooling and the fan is silent with medium PSU load. Unfortunately not only high-quality 105°C capacitors are inside of this power supply used, but also some 85°C capacitors like these Bulk-Caps with a Hold-Up time of approx. 17ms on full load.