ReviewsPower SupplySilverstone Extreme 850R Platinum Review: Size Doesn't Matter

Silverstone Extreme 850R Platinum Review: Size Doesn’t Matter

After hours of putting it into rigorous testing. Here is my detailed review of the Silverstone Extreme 850R Platinum.

Expert Verified By

No Compromises!

Review Summary

With its combination of Platinum efficiency, compact design, and reliable performance, the SilverStone Extreme 850R Platinum emerges as a standout option for users seeking a premium SFX PSU solution. Whether powering high-end CPUs and graphics cards or facilitating mild overclocking, this PSU delivers consistent and stable power output while maintaining low noise levels. While the lack of sleeved wires may be a minor drawback for aesthetically-minded users, the Extreme 850R Platinum excels in meeting the demands of modern gaming and workstation setups within the constraints of small form factor builds.

Hours Tested: 7
Tech4Gamers Recommended Award

  • Performance - 9/10
  • Value - 9/10
  • Build Quality - 8.5/10
  • Efficiency - 9.5/10


  • Efficiency
  • Compact Design
  • Impressive Component Quality
  • Silent Operation


  • Unsleeved Wires

Over the span of my several years in the tech industry, SilverStone has been among the most respectable brands I have had the pleasure of working with. Their long history of success in the field gives you complete confidence. Well, today, I am taking a look at the Silverstone Extreme 850R Platinum. It has Cybenetics Platinum efficiency certification and meets Intel SFX 12V V4.0 specification standards. Let’s see how it performs.

Key Takeaways

  • The SilverStone Extreme 850R Platinum PSU is a standout power supply unit tailored for enthusiast builders seeking high performance in a compact form factor. With its Cybenetics Platinum efficiency certification, it sets a new standard for efficiency and reliability in the SFX PSU category.
  • What I liked about Silverstone Extreme 850R Platinum is its compact design, which is tailored for small form factor builds, offering compatibility with compact cases while delivering robust power output.
  • What I didn’t like about Silverstone Extreme 850R Platinum is the absence of separately sleeved wires may detract from the aesthetics of the build for some users who prioritize visual appeal.

Here are the specifications:

Max. DC Output 850W
Power density 1070W per litre
Combined +3.3V & +5V 100W
Combined +12V 850W
Input Voltage 180 ~ 264 Vrms
Input Frequency Range 47Hz ~ 63Hz
PFC Active PFC. (PF>0.9 at Full Load)
Efficiency ≥89% & <91% overall efficiency
MTBF 100,000 hours
Operating temperature 0°C ~ 50°C
Cooling System Silent 92mm FDB fan
Noise Level 0 dBA minimum
Certification Cybenetics Platinum
Form factor SFX
Dimension 125 mm (W) × 63.5 mm (H) × 100 mm (D)
Weight 1.6kg
Product No. SST-EX850R-PM
Model (safety certification) SST-SX0850MCPT-A
Color Black (lead-free paint)

Packaging and Unboxing

Overall, the packing is top-notch, with the PSU safely enclosed in two layers of polythene and multi-layered black foam. You can find the number of connectors it includes, along with a specs table and other information, on the back of the box. Finally, you can find a list of its key features under the efficiency section.


Let’s have a closer look at the Silverstone Extreme 850R Platinum PSU. This PSU is perfect for small form factor setups and compact cases with its dimensions of 125 mm (W) x 63.5 mm (H) × 100 mm (D) and its weight of under 1.5 kg. In addition, it’s perfect for overclocking and future upgrades to high-end components thanks to its strong single +12V rail design. Furthermore, it features a fully modular design. 

Cable Connections

Cable Connections
Cable Connections

With the exception of the 12VHPWR cable, Extreme 850R comes with the usual group of ribbon cables. Thanks to its softer, more flexible design, the 12VHPWR cable is extremely adjustable. Particularly noteworthy is the fact that flexible flat wires are much more versatile, enabling narrower folding. Even though the cable size is small for easy-to-manage cable management in small form factor PC cases, Silverstone has quite remarkably chosen 16AWG wires for PCIe, EPS & 12VHPWR connectors. The standard 24-pin connector is used along with an independent voltage sense pin for better voltage regulation & control.

The Silverstone Extreme 850R Platinum has the following connections: 

  • 1x 24 / 20-Pin motherboard connector
  • 2x 8 / 4-Pin EPS / ATX 12V connector
  • 2x 8 / 6-Pin PCIe connectors
  • 1x 12+4-Pin 12VHPWR connector
  • 8x SATA connectors
  • 3x 4-pin Peripheral connector
  • 1x 4-pin Floppy connector


Fluid Dynamic Bearing fan from Globe Fan
Fluid Dynamic Bearing fan from Globe Fan

The 92mm FDB fan of the Silverstone Extreme 850R is very quiet, and it has features like intelligent deactivation and delayed shutoff. Silverstone Extreme 850R does have hybrid fan mode where the fan only starts spinning when the load exceeds 150W of load. Fan noise is clearly audible as it has to really work hard for its size, but it’s totally under an acceptable range. Overall, I can say that among the most silent SFX PSUs currently on the market is the Extreme 850R from SilverStone.

Teardown & Component Analysis

Casecom Platform
Casecom Platform

When I finally got to look inside, things started to unfold in a good way. I see a familiar-looking platform from SANR/Casecom, which has been the OEM not only for Silverstone but also for a few other brands in the past with the SFX form factor. I have got to say that SANR seemed to have done a marvelous job in creating this tiny but greatly efficient platform, at least on paper for now, as I have not yet discussed its results and performance.

Though I usually see Interleaved PFC topology on the primary side of the PSU for the Platinum rating these days, Silverstone Extreme 850R instead has adapted for Active PFC, which is mainly found in Gold-rated PSUs, and this is most likely due to the size limitation as Interleaved PFC requires two beefy inductors instead of a single one.

Silverstone has opted for the TO247 package MOSFET for its APFC boost circuit, which is much bigger in size and in terms of power ratings compared to normal TO220 package size MOSFETs that are usually found in traditional ATX size PSUs. Notably, two MOSFETs on the back are most likely responsible for improved Platinum efficiency.

So far, I don’t see any compromises in terms of component quality and design due to size limitations. I think I am getting quite comfortable in getting my hopes high now. Furthermore, for the secondary 12V conversion, Half-Bridge and LLC resonant converter topology is used alongside DC-DC converters for minor 5V and 3.3V rails.

All the major power components, Bridge-Rectifier, APFC’s & Half-Bridge LLC MOSFETs, and Boost Diode, are all incorporated on the same but hefty heatsink, which spreads much farther from the top in order to receive direct airflow from the fan for better heat dissipation.

Regarding heat dissipation, the 12V rail transformer has a somewhat unique design that we often see many OEMs utilizing in their SFX PSUs due to the fact that the main 12V rail transformer provides all the rated output power of a PSU. In this case, a whopping 850W in a very restricted space, SANR has engineered their transformer in a way that it integrates built-in metal fins that act as a heatsink. Thermal pads installed on the back for efficient heat dissipation for back side installed MOSFETs

Moreover, 12V rail MOSFETs reside on the back of the PCB, and there are a decent number of thermal pads for heat dissipation. We also get to see two strange parts on the back that look like SMD MOSFETs, but sadly, there is no information for this component online. I believe them to be SMD MOSFETs and the way they are arranged alongside the bridge rectifier. They may have a very vital role in managing high-efficiency numbers. However, SANR has done a good job in soldering. However, I did find a few not-so-good spots.

That’s probably how Silverstone Extreme 850R is able to get away with using traditional Active PFC design on the primary side instead of superior Interleaved PFC. For the capacitors, which are the most crucial and costly components in terms of their combined quantity. Silverstone has picked up one of the best quality 105C-rated electrolytic capacitors from Japanese manufacturer Rubycon and polymer capacitors from Nichicon, also a high-end Japanese brand.

Overall, I am really impressed with Silverstone for giving the utmost importance to their SFX PSU lineup and choosing a very capable OEM with little to no compromises. Before going to the testing section, it is important to note that we may not see very high-performance numbers compared to our previously tested PSUs, but that’s due to the fact that this is an SFX form factor PSU, which is most likely not going to be used in some of the extreme performance and high overclocking gaming systems.

PSU Load Testing

12V & Minor Voltage Rails Regulation

Applying loads of 20%, 50%, 80%, 90%, and 100% to the 12V rail while maintaining a constant 25W combined load on the minor rails (5V and 3.3V) ensures a comprehensive evaluation of PSU performance. This approach acknowledges that the 12V rail bears the brunt of powering demanding components like the CPU and GPU, hence the need for varying stress levels. Meanwhile, the minor rails, responsible for less power-hungry components such as HDDs, SSDs, and RAM, remain relatively stable with their consistent load.

Load in %            12V        5V          3.3V
20%       12.07V 4.99V 3.34V
50%       12.01V 4.98V 3.34V
70%       11.96V 4.98V 3.33V
90%       11.91V 4.97V 3.32V
100%    11.89V 4.96V 3.33V

Voltage regulation is really outstanding, even with the maximum load. The shorter-length cables also play an important role here

A new standard for excellence in the SFX PSU category

PSU Efficiency

Load in %            Power Factor    Efficiency
20%       0.938 91.59%
50%       0.982 94.21%
70%       0.991 93.78%
90%       0.996 93.63%
100%    0.997 92.21%

Remember I was at first a bit skeptical of Silverstone Extreme 850R for using Active PFC instead of Interleaved PFC? Well, after seeing these impressive efficiency numbers, I am not anymore! SANR and Silverstone have done a remarkable job!

Voltage Ripple Performance

Load in % Voltage Ripple
20% 20mV
50% 20.9mV
70% 24mV
90% 28mV
100% 32mV

Voltage ripple performance is decent when compared to full-size ATX PSUs. However, for the SFX form factor, it’s extremely impressive. People who will be using this PSU are unlikely to turbo up on overclocking, considering that they will be using it in their tiny PC cases where cooling performance is already going to be quite challenging.


Overall temperature performance is really good for its size. The maximum hottest point on the back where 12V MOSFETs are located was found to be 57.4C. I recommend leaving adequate space between the back of this PSU and the rest of the PC components in a small form factor PC case.

12VHPWR Cable Performance On Max Load

included native 12VHPWR cable that easily sustained the constant load of 600W at 11.94V, again due to the use of shorter length cable. You won’t have any issues running even an RTX4080Ti GPU on this PSU.

PRO TIP: While the PSU excels in providing efficient and reliable power delivery, users should exercise caution when pushing the limits of their hardware, particularly in overclocking scenarios.

Should You Buy It?

Buy It If 

✅You prioritize efficiency and space-saving design: The SilverStone Extreme 850R Platinum’s Cybenetics Platinum efficiency certification and compact SFX form factor make it an excellent choice for users seeking high-performance power delivery in a small package.

✅You demand quiet operation: With its Silent 92mm FDB fan and intelligent fan control features, the Extreme 850R Platinum ensures silent operation even under heavy loads.

Don’t Buy It If

❌You require individually sleeved cables: The absence of separately sleeved wires may detract from the aesthetic appeal of your build, particularly if you prioritize visual customization.

Final Verdict

For those who own a high-end CPU and an RTX 4000 series graphics card, SilverStone’s Extreme 850R comes highly recommended. The SilverStone Extreme 850R Platinum stands as a top contender, as it is specifically manufactured with enthusiasts’ PC builders in mind who are seeking a high-quality power supply unit that excels in the SFX form factor.

With its compact design and impressive power delivery capabilities, it caters to small form factor setups and compact cases without compromising on performance or efficiency. As of this writing, it is among the top SFX PSU on the market. It operates silently under low and heavy loads and is 12VHPWR natively compatible. The only thing in which 850R falls short is that it does not come with separately sleeved wires.

Coming Next: SilverStone HELA 1200R Platinum Review

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