Page 3 - Physical Look - Inside
As always, we opened up our NZXT E850 850W power supply to take a detailed look at what is going on inside. Please note that doing this at home will void your ten-year warranty, thanks to the warranty seal NZXT applied over one of the attachment screws. But for the benefit of you, we cracked ours open so you do not need to, haha. There are no user serviceable parts inside.
Disassembling the NZXT E850 850W is quite straightforward with the removal of eight to twelve screws, depending on how far you want to get. Our photo above shows an overhead view of its internal components. Its OEM is Seasonic, one of the best manufacturers of power supplies in the world. This power supply is based off the FOCUS Plus Gold platform, which we have reviewed a model from back in September 2017. At first glance, the build quality appears to be excellent. There are four main heatsinks inside. One medium one and one large one is located on the primary side, while two smaller sized heatsink resides on the secondary side, all of which are unpainted.
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. Seasonic has always done a great job in the past to make sure their power supplies met or exceeded the recommended requirements, and the NZXT E850 850W is no exception. The NZXT E850 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. Considering how many modern-day PSUs have missing MOVs, I am happy to see it here, as this component is used to stabilize spikes from the AC line. A Champion CM6500 PFC controller can be spotted at the back of the PCB.
On the primary side, we can see one Japanese made Hitachi capacitor. 100% Japanese made capacitors are specified on the marketing material, so this is to be expected. Our 850W version of NZXT's latest E-series power supply incorporates one 680µF x 400V capacitor. It is rated at 105c; whereas more value-oriented power supplies usually use 85c rated capacitors.
The active PFC circuit featured on the NZXT E850 850W uses two Lite-On Semiconductor GBU1506 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 are able to keep up. Further down the line, on the outside of the largest heatsink, we can see two Infineon IPP60R190P6 power transistors. This MOSFET model is certified for up to 12.7A at 100c. A STMicroelectronics STTH8S06 boost diode is placed right next it. Four Greatpower GPT13N50DGN220FP power MOFSET transistors are used as the main switchers on the E850 850W power supply. Each Greatpower GPT13N50DGN220FP MOFSET can deliver up to 13A at 25 degrees Celsius continuously. These transistors present a maximum resistance of 0.49 ohm 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 secondary side, we can see more Japanese made capacitors from Nippon Chemi-Con and Nichicon 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 Nexperia PSMN2R6-40 MOSFETs are responsible for generating the +12V output, located at the back of the PCB, not shown. The PSMN2R6-40's rated continuous drain current is 100A at 100c. It has a RDS(on) value of 0.0028 ohm maximum and 0.0020 ohm typical. A Texas Instruments UCD3138064A digital power supply controller gives the NZXT E850 850W its "digital" designation. Strictly speaking, the Seasonic FOCUS Plus Gold platform is analog, but the UCD3138064A chip interfaces with NZXT's CAM monitoring software to provide vital statistics about this PSU, which we will take a closer look at on the next page. Meanwhile, a Weltrend WT7527 monitoring IC provides over/under current and over/under voltage protection. Champion's CM6901 is the PWM switching controller. 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 entire rear panel for the modular cable sockets. All modular sockets at the bottom are soldered directly to the main PCB after the secondary stage to reduce power transmission loss. The output connector configuration can be seen on the previous page. Overall, the internal build quality of NZXT's E850 850W power supply is excellent -- something we would expect from a Seasonic built unit. 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 NZXT E850 850W is generally very good with regards to the selection of components used under the hood; appropriate for its performance class.
Lastly, we see a 120mm fan that provides cooling to the NZXT E850 850W's internal components. It is connected to the mainboard using a 2-pin connector. A 120mm fan is rather small nowadays for a power supply with a bottom mounted fan, but if not a lot of heat is being generated, it should not be much of an issue. A 120mm fan is used to keep the enclosure as small as possible, considering the E850 is only 150mm deep. Ong Hua is the fan OEM, with HA1225H12F-Z as the model number, as shown in our photo above. Further research indicates the HA1225H12F-Z is a fluid dynamic bearing fan specified at 0.58A for a maximum of speed of 2200 rpm. Fans with fluid dynamic bearings generally have much longer lifespans compared to sleeve bearing fans, and is quite suitable for this application.
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion