Page 3 - Physical Look - Inside
As always, we opened up our Cooler Master V850 Gold i multi 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, thanks to the warranty seal Cooler Master applied over one of the attachment screws. 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 V850 Gold i multi 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. Its OEM is Chicony Power Technology, a Taiwan-based OEM since 2008. They have manufactured power supplies for Lenovo and HP systems as well as the Sony PlayStation. It features an LLC half bridge topology with DC-to-DC converters. At first glance, the build quality appears to be excellent. There are three main heatsinks inside, all unpainted, with two larger ones located on the primary side and one small one on the secondary 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 V850 Gold i multi 850W is no exception. The Cooler Master V850 Gold i multi 850W has one metal oxide varistor, two metalized polyester X-capacitors, six ceramic Y-capacitors, and two ferrite coils. This is two times the amount of X and three times the amount Y capacitors than recommended. Considering some PSUs have missing MOVs, I am happy to see it here as this component is used to stabilize spikes from the AC line.
The active PFC circuit featured on the Cooler Master V850 Gold i multi 850W uses two Taiwan Semiconductor GBU15L05 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 Infineon IPP60R120P7 power MOSFETs. Each is specified for up to 16A at 100c. These transistors present a maximum resistance of 120 mΩ and typical resistance of 100 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.
On the primary side, we can see one Japanese brand Toshin Kogyo 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 V-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.
A Cree C6D10065A Silicon Carbide Schottky boost diode is placed on the opposite side of the second heatsink. Two Infineon IPA60R120P7 power MOSFETs on the same heatsink are used as the main switchers on the V850 Gold i multi 850W power supply. Each is specified for up to 16A at 100c. These transistors have a maximum resistance of 120 mΩ and typical resistance of 100 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 and Nichicon 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. The MOSFETs responsible for generating the +12V output is located under the small heatsink on the secondary side, therefore I was unable to identify the part number. An Unisonic Tech LM7912L linear voltage regulator is spotted by itself near the +12V MOSFETs.
Four Alpha & Omega AON6144 MOSFETs are responsible for generating the +5V and +3.3V outputs, located on the vertical board parallel to the rear connector board. The AON6144's rated continuous drain current is 89A at 100c. It has an RDS(on) value of 2.4 mΩ maximum and 2.0 mΩ typical. An ANPEC APW7159 synchronous buck PWM controller can be seen on the same board as well.
On the vertical board perpendicular to the rear connector board, we can spot a Weltrend WT7502R monitoring IC for over/under current and over/under voltage protection and an ARM Cortex-M0 based Nuvoton NuMicro M032EC1AE MCU.
There are few components of interest at the bottom of the PCB. Here, we can spot a STMicroelectronics STU4N80K5 MOSFET, Advanced Power Electronics AP6N6R5LMT-L MOSFET, and an Infineon ICE2PCS0 PFC controller chip. The datasheets for all components mentioned in this review can be found on their respective manufacturer's websites.
At the back, we have a large daughterboard covering the majority of the rear panel for the modular cable sockets. All modular sockets at the bottom are soldered directly to the main PCB after the secondary stage. Pin headers join the mainboard and daughterboard 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 V850 Gold i multi 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 V850 Gold i multi 850W is generally good with regards to the selection of components used under the hood.
Lastly, we can see a 135mm fan that provides cooling to the Cooler Master V850 Gold i multi 850W's internal components. It is connected to the mainboard using a 2-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's sticker shows this is a Snowfan YY14025M12B, as shown in our photo above. According to the manufacturer data sheet for this model number, this is supposed to be a 140mm fan, but I physically measured it, and it is indeed 135mm per Cooler Master's specifications. The PSU specifications also states a fluid dynamic bearing fan, but the model number seems to suggest a ball bearing. Given the incorrect dimensions, I would not be surprised if the model number on the sticker is probably inaccurate. Just for reference, the actual YY14025M12B is rated at 0.4A for a maximum speed of 2000 RPM, 101.81 CFM airflow, 2.75 mmH2O air pressure, and 40.6 dBA of noise. 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
