SilverStone Strider Gold S ST85F-GS 850W (Page 3 of 4) | Reports

Page 3 - Physical Look - Inside

As always, we opened up our SilverStone Strider Gold S ST85F-GS 850W power supply to take a detailed look at what is going on inside. Please note that doing this at home will void your 3-year warranty, thanks to the warranty seal SilverStone applied over one of the attachment screws. But for the benefit of you, we cracked ours open so you don't need to, haha. There are no user serviceable parts inside.

Disassembling the SilverStone Strider Gold S ST85F-GS 850W is quite straightforward, with the removal of four screws. As with the Strider Gold Evolution ST75F-G 750W, Strider Gold ST75F-G 750W, Strider Gold ST65F-G 650W, and Strider Plus ST75F-P 750W, the Strider Gold S ST85F-GS 850W's OEM is Enhance, a well regarded OEM since 1986. Our photo above shows an overhead view of its internal components. At first glance, the build quality appears to be excellent, as one would expect from the company. There is only one aluminum heatsink inside the power supply; stretching from north to south with teeth at the top to enhance heat dissipation.

A quick tug on the shell, 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. SilverStone has always done a great job in the past to make sure their power supplies met or exceeded the recommended requirements, and the Enhance based ST85F-GS is no exception. The SilverStone Strider Gold S ST85F-GS 850W has two ferrite coils, one metal oxide varistor, four metalized polyester X-capacitors, and four ceramic Y-capacitors. This is four times the amount of X capacitors and twice the amount 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 along with a TVS diode.

On the primary side, we can see two Japanese brand Nippon Chemi-Con capacitors connected in parallel. Japanese brand capacitors are usually what we expect from something in this price range, so this is nothing surprising. Our 850W version of SilverStone's Strider S series incorporates two 330µF x 420V capacitors for a total capacitance equivalence of a single 660µF x 420V capacitor (Remember that values add up when capacitors are hooked up in parallel, unlike resistors). These units are rated at 105c; whereas more value oriented power supplies usually use 85c rated capacitors.

The active PFC circuit featured on the SilverStone Strider Gold S ST85F-GS 850W uses one Lite-On Semiconductor GBU15L06 glass passivated bridge rectifier. At 115V, the maximum rectified forward current capacity with heatsink is 15A each, so you can theoretically pull up to 1725W (15A * 1 diode * 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. Two Infineon IPP50R140CP power MOFSET transistors are used on the active PFC circuit on the SilverStone Strider Gold S power supply, with an NXP BYC15-600 power diode. One STMicroelectronics STP21N90K5 power MOSFET and one Fairchild Semiconductor FQP9N90C N-Channel MOSFET can also be found on the lone aluminum heatsink. Each Infineon IPP50R140CP MOFSET can deliver up to 15A at 100 degrees Celsius continuously. These transistors present a maximum resistance of 0.14 ohm when turned on; with a typical resistance of 0.13 ohm according to the manufacturer's data sheet. The STMicroelectronics STP21N90K5 MOSFET can deliver up to 11.6A at 100 degrees Celsius continuously; with a maximum resistance of 0.299 ohm, and a typical resistance of 0.25 ohm. 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 mainly Taiwanese capacitors from Taicon and Su'scon rated at 105c. As with modern high efficiency power supplies, all rectifiers produces 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. A Texas Instruments CSD86350Q5D half bridge power block can be found at the back of the PCB. The DC-to-DC converter has one ANPEC APW7073 synchronous buck PWM controller for each rail. Eight International Rectifier IRFH7004PBF MOSFETs are responsible for the rectification process. The IRFH7004PBF's rated continuous drain current is 164A at 100c, and a pulsed drain current of 1247A. Drain source voltage is rated at 40V, and a RDS(on) value of only 0.0011 ohm. Meanwhile, a Silicon Touch PS232S monitoring IC provides the Strider Gold S ST85F-GS's OVP, UVP, and OCP protection. 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. There is nothing special going on here electrically; all sockets are connected to the main circuit board after the secondary stage by a bundle of wires. The output connector configuration can be seen on the previous page. Overall, the internal build quality of SilverStone's Strider Gold S ST85F-GS 850W power supply is excellent -- something we would expect from what we have seen from the company in the past. Components are arranged pretty well for optimal cooling with minimal wires running around inside, and solder points on its green PCB is very clean in general. I would say the SilverStone branded, Enhance built ST85F-GS is generally very good with regards to the selection of components used under the hood.

Lastly, we see a 120mm fan that provides cooling to the SilverStone Strider Gold S ST85F-GS 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 Strider Gold S is only 150mm deep. ADDA is the fan OEM, with AD1212HS-A71GL as the model number, as shown in our photo above. Further research indicates the AD1212HS-A71GL is a sleeve bearing fan specified at 0.44A for a maximum of speed of 2200 rpm. The rated airflow is 85.2 CFM at 39.1 dB of noise.

Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion