Silverstone Strider 850w ST85F PSU Page: 1

Back in October, Silverstone gave me the first look at their latest 750w modular power supply named the ST75F. This PSU proved to be a big improvement over its predecessor the ST60F, but still suffered from some of its original flaws. Today we're back again, and this time looking at the ST85F. In case you hadn't already guessed, the ST85F is the latest in the line of Silverstone's modular units, based around the ST60F and ST75F but with a total power output of 850w and a few extra tweaks along the way.

Visually the ST85F is the same as its predecessors in almost every way (externally at least), and for this reason I'd suggest that anybody who has already read our ST75F review should turn to pages 5, 6 & 7 to avoid a severe case of Déjà Vu. Over these few pages I'll be finding out what changes have been made internally, and if they have had any effect on the power supply's performance.


Having reviewed quite a few Silverstone products on Overclock3D I was fairly confident of what to expect from the ST85F. The unit comes in a double walled black cardboard box with a design that ties in with the rest of the Silverstone range.

This standardised design makes it easy to pick out Silverstone products among the other brands, and the unit's specifications are clearly visible on all sides of the box.

Silverstone ST85F Box Silverstone ST85F Box

In all honesty, nothing much has really changed between the packaging design of the ST60F, ST75F and ST85F. The front and top of the box still show pictures of the power supply along with its vital statistics. However, unlike it's predecessor, the ST85F utilises dual +12v rails, rather than the quad +12v rails used on previous models. This step backwards could well be a good move by Silverstone, ensuring that there is enough power on the 12v rails for the most hungry graphics cards.

Silverstone ST85F Box Silverstone ST85F Box

Turn the box around to the side and we can see that Silverstone have included some more detailed information on the unit. A lot of focus is on its safety features, which include OCP (over current protection), UVP (under voltage protection), OVP (over voltage protection) and SCP (short circuit protection).

Silverstone ST85F Contents Silverstone ST85F Contents

As with the previously reviewed ST75F, the ST85F is protected from scratches by a clear plastic bag with no other padding to protect the unit from larger knocks included. I know that I've complained about this before, but it would be nice to see Silverstone paying a bit more attention to packaging even if just for aesthetic appeal.

The ST85F package includes the following items:

• Silverstone ST85F manual.
• Black case screws.
• Power cord.
• ST85F Power Supply.
• Canvas cable bag.

Silverstone Strider 850w ST85F PSU Page: 2

The following information has been taken directly from Silverstone's Website:

With continuous combined +12V output of 64A , the 850W addition to SilverStone's Strider family has all that is capable of running a high-end system. Housed in the same environmentally friendly casing as the ST 75F , with 100% modular cable system and high quality cable bag, this power supply package is not only more advanced; it is also a cinch to manage. Cooled with a bigger and quieter 135mm fan, the ST 85F is an awesome all around power supply that delivers performance, optimal efficiency, and superior user comfort in its class!

• Dual +12V with continuous 64A combined output
• 100% modular cables with cable bag
• Support dual PCI-E 8 pin connectors & quad PCI-E 6 pin connectors
• Silent running 135mm fan
• Support for ATX 12V 2.2 & EPS 12V
• Active PFC
• Efficiency greater than 80%

Silverstone ST85F Specs

In addition to Silverstone making the decision to 'downgrade' the ST85F to two +12v rails instead of the original four, they have also incorporated the latest 8-Pin PCI-E connectors due to be used in upcoming graphics cards. The ST85F is also shown to be 2dBA quieter at idle than the previous ST75F model most likely owing to it's slightly larger 135mm fan.

Silverstone Strider 850w ST85F PSU Page: 3

The ST85F is finished in a matt black lead-free paint and has a minimal amount of shine. As you can see from the image showing the top of the ST85F below, the sample unit I received had several scratches in its paintwork.

A more severe case of this was seen on the previous ST75F review and the problem raised with Silverstone. However, as the ST85F wasn't packaged any better it looks like we can see this problem repeating itself.

Silverstone ST85F Back Silverstone ST85F Top

Silverstone ST85F LED Silverstone ST85F LED

The back of the unit is vented with a honeycomb mesh grill complete with an LED status indicator that changes from red to green when the PSU is powered on. You may also notice that there is no 110/240v switch present. This is because the ST85F, like many other modern PSU's is able to auto-detect the input voltage.

A welcome change to the ST85F over the previous Strider models has to be the use of a new power switch. Many people seem to have had problems with the switches on the older Strider units and hopefully this change has permenantly resolved the issue.

Silverstone ST85F Side Silverstone ST85F Bottom

I've always admired the Silverstone Strider modular range for providing the ability to tweak the units output voltages via adjustable potentiometers on the side of the unit. However, on the ST85F it would seem that Silverstone have done away with this great feature. Lets hope that the rail stability is good enough to warrant not needing this.

Due to the increased fan size on the ST85F (135mm vs 120mm), the bottom of the unit is now almost entirely consumed by the fan and it's grill. This makes the unit slightly more visually appealing than the ST60F and ST75F that utilised a 120mm fan placed in an off-centre position.

Silverstone ST85F Front

Just like the ST75F, the ST85F comes with a total of 11 modular connectors. You will also notice that the ST85F is fully modular, and therefore all cables including the ATX and EPS connectors can be removed if required.

Silverstone Strider 850w ST85F PSU Page: 4
Cables & Connectors

The ST85F uses exactly the same type of cables as the ST75F. As a result, all cables on the ST75F are professionally sleeved in black mesh right up to the first connector. The sleeving is then held in place with sticky tape and finished off with black shrink-wrap.

Silverstone ST85F Cables Silverstone ST85F Cables

Silverstone ST85F PCI-E [pics]

With 850w on tap and two high-amperage +12v rails, there is no reason why the ST85F wouldn't be capable of powering any kind of high-end SLI or Crossfire configuration. For this reason Silverstone have included 2x PCI-E cables, each with 2 further PCI-E connectors 'piggy-backed' to give support for the latest line of 8800GTX GPU's. Also included in the box with the ST85F are two 8-Pin PCI-E cables in a similar configuration, for compatibility with future PCI-E cards.

Silverstone ST85F Cables Silverstone ST85F Cables

The ATX connector on the ST85F is native 24-pin. However, as you can see above, a small block of 4 connectors can be broken off to switch the connector to 20-pin, and thus make it compatible with older motherboards. As many motherboards still make use of the P4-12v 4-Pin connector, Silverstone have chosen to include two separate cables for P4-12v (4-pin) and EPS12v (8-pin) standards.

Silverstone Strider 850w ST85F PSU Page: 5
Looking Inside

Its fair to say that I've opened up quite a few Silverstone Strider units over the past year, and barring a few upgraded capacitors and transformers not much has ever changed. Will this be the case for the ST85F, or does it have something new up its sleve for me to talk about?

Silverstone ST85F Internals Silverstone ST85F Internals

Silverstone ST85F Internals Silverstone ST85F Internals

In comparision with the ST75F internals (seen here) the ST85F does look somewhat less crowded. One of the most noticable changes is the downgrade from two +12v transformers to just one - most likely owing to the reduction from four +12v rails down to two. We can also see that the main capacitor has been downsized and several of the smaller wire-wound coils are no longer present. This minimalistic approach may sound worrying, but as we've seen many times in the past, it's not always the bulkiest power supplies that are the best performers.

Silverstone ST85F Fan

The Strider makes use of a standard 135mm brushless fan manufactured by Young Lin Tech. I was unable to find any definite figures for this fan, but as the Silverstone specs suggest, the fan is rated at 22dbA when running at top speed.

Silverstone Strider 850w ST85F PSU Page: 6
Load Testing

In order for the results from all current and future PSU reviews to remain fair and comparable, Overclock3D uses a custom built Power Supply load stress tester. The tester will be placing the following loads on each of the Strider's rails:

  Idle Load
+3.3v Rail
+5.0v Rail
+12v1 Rail
+12v2 Rail5a20a

As some power supplies produce obscure voltage outputs when running with 0% load, the Idle testing simulation will be produced by placing each rail under a small load similar to what would be expected from a mid-range PC. Load testing results are obtained by placing the unit under the maximum load selectable on the OC3D equipment without tripping the OLP (Over Load Protection) on the power supply.

Silverstone ST85F 3.3v Rail Silverstone ST85F +5v Rail

Silverstone ST85F +12v1 Rail Silverstone ST85F +12v2 Rail

All rails on the ST85F remained well within ATX specifications when placed under full load, with the most fluctuation being exibited on the +5v rail. Comparing the results of the ST85F against the ST75F we can actually see that the ST75F suffered less (over half) as much fluctuation on the +12v rails. This could well be due to the ST75F having quad +12v rails, but never less it would have been nice to see the ST85F performing on-par with its predecessor.

Efficiency Testing

Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains against the power (in watts) consumed by the OC3D power supply stress tester. These results may not be 100% accurate, but have proven to be extremely close to results obtained from professional equipment.

Silverstone ST85F Efficiency Silverstone ST85F Efficiency

At idle the ST85F was placed under a total load of 203 watts with a recording of 249 watts consumption being obtained from the mains. Therefore the efficiency of the ST85F at idle worked out to be 81.5%.

Increasing the load on the unit produced even more favourable results, with the ST85F managing 83.4% efficiency when being placed under a total load of 646 watts.

Noise Testing

Possibly the hardest part of any PSU review is summarising the level of noise given out by the unit. The threshold for what is considered 'noisy' varies from person to person and therefore what I may consider a quiet unit, another person may consider extremely loud. A common way to resolve this issue is to use a dBA meter to measure the units noise level, however this doesn't take into account the pitch (type) of noise emitted and whether it is likely to irritate end users.

For this reason OC3D records all power supplies at idle and load in wav format for you to make your own informed decisions. All recordings are taken at 30cm away from the PSU and outside of a PC case. You will need to remember that noise levels will be reduced by varying amounts once the PSU has been installed inside your PC enclosure.

Idle Recording - Download
Load Recording - Download

Silverstone Strider 850w ST85F PSU Page: 7

The ST85F is a very capable power supply that benefits from the quietness of a 135mm fan, has a fully modular cabling system and support for the very latest and upcoming PCI-E 8-Pin graphics cards. Voltage stability and Efficiency are good and Silverstone have also rectified the issue with faulty power switches found on some of the previous Strider series units.

On the down side, it's a shame to see that Silverstone decided to get rid of the adjustable pots (for fine-tuning voltages) on the ST85F as this is a highly desireable feature many enthusiasts will miss. Internal packaging (or lack of) still seems to be a problem, with the Strider falling behind PSU's from other manufacturers at same price point, who manage to use styrofoam inserts at the very least.

• Fully modular design.
• Quieter than predecessors thanks to 135mm fan.
• Support for very latest graphics cards.
• Dual rail design for better distribution of available power.
• Reasonable voltage stability and efficiency.

• Missing the adjustable pots found on previous modular Strider units.
• Voltage stability not quite on-par with the ST75F (possibly due to dual vs. quad rail).
• Packaging still needs work. Some foam inserts make all the difference!

Recommended Award

Thanks to Silverstone for providing this unit for review.

Discuss this review in our forums.