Page 3 - Physical Look - Inside
As always, we opened up our Cooler Master XG850 Plus Platinum 850W power supply to take a detailed look at what is going on inside. Please note that doing this at home will void your 10-year warranty. It is great it comes with a 10-year warranty, which is the industry standard for performance PSUs. For the benefit of you, we cracked ours open, so you do not need to. There are no user serviceable parts inside.
Disassembling the Cooler Master XG850 Plus Platinum 850W is quite straightforward with the removal of four to ten screws, depending on how far you want to get. Our photo above shows an overhead view of its internal components. Cooler Master designed the platform in-house, but the actual OEM is Huizhou Xin Hui Yuan Tech, otherwise known as Fusion Power. At first glance, the build quality appears to be excellent. There are two main heatsinks inside, all painted black and located on the primary side.
Pulling the enclosure apart and we got straight to the internal inspection. The transient filter stage is the first input stage of a computer power supply, so we will take a look at that first. Cooler Master has always done a great job in the past to make sure their performance power supplies meet or exceeds the recommended requirements, and the XG850 Plus Platinum 850W is no exception. The Cooler Master XG850 Plus Platinum 850W has one metal oxide varistor, two metalized polyester X-capacitors, four ceramic Y-capacitors, and two ferrite coils. This is two times the amount of X and Y capacitors than recommended.
On the primary side, we can see one Japanese brand Nippon Chemi-Con capacitor. 100% Japanese brand capacitors are specified on the marketing material, so this is to be expected. Our 850W version of Cooler Master's latest XG-series power supply incorporates one 680µF x 450V capacitor. It is rated at 105c; whereas more value-oriented power supplies usually use 85c rated capacitors.
The active PFC circuit featured on the Cooler Master XG850 Plus Platinum 850W uses two MCC GBU15KL bridge rectifiers attached to opposite sides of the first heatsink. At 115V, the maximum rectified forward current capacity with heatsink is 15A each, so you can theoretically pull up to 3450W (15A * 2 diodes * 115V) from the bridge rectifier at 100% efficiency. Of course, this is limited by the fact that it is not 100% efficient and also neglects the fact that not every component in the system is able to keep up.
Further down the line, on the outside of the second heatsink, we can see two NCE NCE65TF099 power MOSFETs. Each is specified for up to 24A at 100c. These transistors present a maximum resistance of 109 mΩ and typical resistance of 89 mΩ when turned on according to the manufacturer's data sheet. This on characteristic is called Static Drain-Source On-Resistance, or commonly abbreviated as RDS(on). The more efficient the component is, the lower the RDS(on) value, since it wastes less power with lower resistance.
A Panjit PCDP0865G1 Silicon Carbide Schottky boost diode is placed on the second heatsink. Two NCE NCE65TF130 power MOSFETs next to the bridge rectifiers on the first heatsink are used as the main switchers on the XG850 Plus Platinum 850W power supply. Each is specified for up to 18A at 100c. These transistors have a maximum resistance of 140 mΩ and typical resistance of 110 mΩ when turned on. Other components that can be spotted in the primary side include a Champion CM6901T6 SLS, SRC/LLC + SR resonant controller and a Champion CM6500UN PFC controller on the back of the PCB.
On the secondary side, we can see more Japanese brand Nippon Chemi-Con capacitors rated at 105c. As with modern high efficiency power supplies, all rectifiers produce the +12V out, while the +5V and +3.3V outputs are generated from the +12V output using a DC-to-DC converter within the power supply unit. Four Infineon BSC010N04LS MOSFETs are responsible for generating the +12V output, with two located on each of the riser boards. The BSC010N04LS's rated continuous drain current is 178A at 100c. It has an RDS(on) value of 1.0 mΩ maximum and 1.0 mΩ typical. Meanwhile, the Excelliance MOS EM8569C PWM converter can be seen immediately after the primary stage.
At the back, we have a large daughterboard covering the entire rear panel for the modular cable sockets. Two Excelliance MOS EMB04N03 and two Excelliance MOS EMB07N03 MOSFETs located here generate the +5V and +3.3V output from the +12V rail. The EMB04N03's rated continuous drain current is 55A at 100c. It has an RDS(on) value of 4.0 mΩ maximum and 3.2 mΩ typical. The EMB07N03's rated continuous drain current is 17A at 100c. It has an RDS(on) value of 7.0 mΩ maximum and 5.5 mΩ typical. ANPEC's APW7159C is the PWM switching controller. The datasheets for all components mentioned in this review can be found on their respective manufacturer's websites.
All connectors on the daughterboard are directly soldered to the main PCB to reduce power transmission loss. The output connector configuration can be seen on the previous page. Overall, the internal build quality of Cooler Master's XG850 Plus Platinum 850W power supply is excellent. Components are arranged very well for optimal cooling with minimal wires running around inside, and solder points on its black PCB is quite clean in general. I would say the Cooler Master XG850 Plus Platinum 850W is generally good with regards to the selection of components used under the hood, but some of the manufacturers are not commonly seen in high-end PSUs.
Lastly, we can see the LCD controller board and a 135mm fan that provides cooling to the Cooler Master XG850 Plus Platinum 850W's internal components. It is connected to the mainboard using a 3-pin connector. A 135mm fan is only marginally smaller than the 140mm maximum you can fit in an ATX power supply, and it is beneficial in most cases in providing lots of airflow at lower speeds for quiet operation. The fan is a Cooler Master DF1352512FDHN, as shown in our photo above. It is a fluid dynamic bearing fan with a clear impeller for ARGB LEDs specified at 0.6A for a maximum speed of 1800 RPM, but capped at around 750 RPM by design. Fans with fluid dynamic bearings generally have much longer lifespans compared to sleeve bearing fans and is quite suitable for this application.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests, Software, Conclusion
