SilverStone Zeus ST85ZF 850W Power Supply

Today I have a SilverStone Zeus ST85ZF up on the desk. This is bound to be something special as I have done a number of SilverStone power supply reviews, and whether the product is from Enhance or Etasis, the review is always ultimately positive. The ST85ZF is SilverStone’s 850W flagship power supply, so expectations are high.

SUPPLIED BY: SilverStone
PROD LINK: ST85ZF Product Page
PRICE: > $300
Price is at the time of testing!

SilverStone Zeus ST85ZF 850W Box

The top of the box has a number of bullet points. We can put a check on all of these, but need to confirm the last one. The ST75ZF made the same efficiency claim of 80% or better, but I was unable to reproduce this.

SilverStone Zeus ST85ZF 850W Fan

The ST85ZF is cooled by a single 80MM fan. The fan is mounted on the INSIDE of the PC’s chassis, so the power supply itself will likely baffle most of the fan noise.

SilverStone Zeus ST85ZF 850W

The back of the ST85ZF is a giant grill with a mammoth on/off switch. There’s an LED that is red when the PSU is in stand by and turns green once the PC is live.

SilverStone Zeus ST85ZF 850W Features

There’s some great product shots on the side of the box. Internal shots and pictures of the cables are included here.

Speaking of cables, lets take a look at what’s coming out of the ST85ZF….

SilverStone Zeus ST85ZF – Cabling
Type of connector:
ATX connector 24
2 x 2 12V connectors 0*
2 x 3 PCI-e 4
8-pin Xeon/EPS connector 1
6-pin Xeon/AUX connector 1
5.25″ Drive connectors 6
3.5″ Drive connectors 2
SATA Drive power connectors 6
Fan only connectors (thermostatically controlled 12V only) 0
* An 8-pin to 4-pin adapter is included that combines +12V1 and +12V2

24-Pin ATX Connector

You’ll see that there’s only a 24-pin main ATX Connector instead of a 20/24. Realistically, you would not need this PSU and still have a 20-pin connector on your motherboard.

There’s also six 5.25″ peripheral Molexes, six SATA and two floppy power connectors. This should be enough for most of us, especially if you’re using the SATA power connectors for your hard drives.

SilverStone Zeus ST85ZF Accessories

Inside the small parts box, we actually have less parts than we did in the ST75ZF. That’s because the ST75ZF had a number of PCI-e adapters so PCI-e connectors can be added for either rail distribution purposes or for OEM quad SLI. The ST85ZF has four fixed PCI-e connectors across three different 12V rails (we’ll get into that more later) so adapters aren’t needed. But because the ST85ZF only has an 8-pin EPS+12V connector, an adapter is needed to bring this down to a four pin ATX+12V motherboard.

We also get a manual, which is very well written, a power cord and a bag of zip ties.

SilverStone Zeus ST85ZF Cables

Most of the cables are sleeved, although they are not sleeved all of the way to the ends. The peripheral connectors still are not sleeved, though. The connectors are actually labeled as to what rail each connector is providing 12V from. That’s cool!

Speaking of rails, let’s take a look at all of them and how much power each one is set to put out…

SilverStone Zeus ST85ZF – DC Output
DC Output +3.3V +5V +12V1 +12V2 +12V3 +12V4 -12V +5VSB
24A 30A 18A 18A 18A 18A 0.5A 3A
Max Combined Watts 180W 840W 6W 15W

The way the 12V rails are distributed are as follows:

  • 12V1: CPU-1. Typically powered through the 4-pin connector of a power supply. On the ST75ZF, power for CPU-1 is provided by the first two 12V wires on the 8-pin EPS+12V connector.
  • 12V2: CPU-2. Typically, dual CPU motherboards that would require each CPU have it’s own 12V rail would get it’s power from the second two 12V wires on the 8-pin connector. SilverStone also puts the SATA connectors on this rail as well as PCI-e connector #3.
  • 12V3: This rail powers many things. The EPS AUX 6-pin is on this rail, as is all of the Molex connectors (used for hard drives, floppy and optical drives, fans, lights, etc.) and the main ATX connectors (powers fan headers and slot powered cards that require 12V.) PCI-e connector #4 is also on this rail.
  • 12V4: This rail is dedicated for use with PCI-e connector 1 & 2.

SilverStone Zeus ST85ZF Cables