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Silverstone Zeus 750w ST75ZF Quad Rail PSU Page: 1
Introduction

Silverstone are fairly new players in the PSU market, but have already made a great name for themselves, using only the best manufacturers to build their units whilst also managing to keep costs low.

Today I'm going to be taking a look at the recently released Zeus 750w unit, which looks and feels like a total beast!

Packaging

Silverstone have clearly spent some time (and money) making their packaging stand out and also look professional at the same time. You can almost tell by the box alone that this is one serious PSU.

Both the front and top of the box display the same vital statistics: Quad +12v rails, Dual PCI-E (it's actually got 2 extra add-in PCI-E connectors too), 4 SATA connectors...you get the idea. Also on the box are a couple pictures of the unit, Cleary slowing off some of its beefy internals through the honeycomb ventilation.

The sides of the box give a little bit more in-depth information about the specs of the unit. Here we see 4x +12v rails each rated at 18a (with a max combined output of 60a), a +3.3v rail rated at 28a and a +5v rail rated at 30a.

With the noise level rated at 24dBA minimum this could prove to be a fairly noisy unit - but we'll find out for sure later on in the review.

Open up the box and the first thing you will be presented with is the PSU manual and a separate sheet of paper explaining the layout of 4 +12v rails on the Power Supply (see Page 2 for close-up).

The unit itself is sandwiched in-between two cardboard layers, each padded out with Styrofoam shapes to protect all corners of the PSU. Also included is a small cardboard box containing the power cord, screws, cable ties, an 8-pin to 4-pin PV-12v converter, and two additional PCI-E connectors.

The bundle of cables are contained within a bubble-wrap sleeve and tied together with a large cable-tie.

Silverstone Zeus 750w ST75ZF Quad Rail PSU Page: 2
Specification

The following specification has been taken in most part from Silverstone's website:

- Quad +12V rail for superior performance
- Dual PCI-E 6pin connectors (SLI & CrossFire ready)
- Industrial class components
- Support for ATX 12V 2.2 & EPS12V
- Active PFC
- Efficiency greater than 80% (max. 86%)

The following image is taken of the +12v rail layout insert included with the Power Supply:

As we can see, Priority is given to CPU1, CPU2 and VGA1, VGA2. VGA3 and VGA4 share their power with the molex connectors, which under most circumstances shouldn't cause any problems - but it really depends on how many high power consumption devices you are planning on running from the molex connectors (12v water pumps for example).

With the +12v4 rail peaking at 22a, this should be enough to power the latest generation of ATI cards (x1900xtx) even when used in crossfire mode.

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Appearance

With dimensions of 150 mm (W) x 86 mm (H) x 180 mm (D) this unit is slightly larger than your average Power Supply. People with small cases, or cases that make use of PSU 'cages' should definitely take some measurements before purchasing this PSU to avoid disappointment.

Silverstone have opted to keep it 'plain and simple', putting the unit alongside the likes of PCP&C and Zippy in the looks department. The unit is sprayed in Black, Lead-Free paint, which is actually quite easy to scratch off by accident (oops).

On the side of the unit is the specification sticker, containing the usual warnings and information about the power supply along with its rated output for all of the rails.

The back of the Power Supply has a mesh grill which allows for an unrestricted flow of air to pass from the 80mm fan through the components and out of the case.

As you can see, the unit also has an LED which shows you the current status. When switching the Power Supply on the LED turns from Red to Green. Only when the LED is Green is DC power supplied to the rails. I must admit that I also accidentally shorted out the power supply, at which point it cut all power and the LED switched to Red.

The Zeus auto-detects the input voltage, and therefore has no switch to manually change the voltage between 110/230v at the back of the unit.

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Connectors

Now this is where things start to get interesting. The Zeus has been designed with the most modern systems in mind, providing backward compatibility by means of extension cables included in the extra's box that comes with the unit.

Only the ATX, 8-Pin and PCI-E connectors are sleeved in black material, which is a bit of a shame and leaves me wondering why they didn't sleeve the rest. Granted unsleeved cables are easier to hide and take up less space when bunched together, but its always easier to remove sleeving than it is to add it.

Above you can see the additional 2 PCI-E connectors which can be used to power a further 2 graphics cards in your system (Quad SLI). The idea is quite cumbersome as one of the connectors is merely just one of the Molex-to-PCIE connectors you would receive in a box with a new graphics card. The other connector plugs into what is referred as the "Aux 6-Pin Connector". I'm not sure if this has any other uses as yet, but the manual certainly doesn't mention any.

It is also worth mentioning at this point that the PSU is NOT Quad-SLI certified. So don't start moaning if it can't run 4x 7900GTX's!

EDIT: 12/05/06

Silverstone have confirmed that they are currently in the process of obtaining Quad SLI Certification for this unit and are just awaiting Stickers and other media before they can promote the unit as Quad SLI Certified.

Here we see the EPS12v (8-pin) connector with the ATX12v (4-pin) extension cable attached. Its good to see that Silverstone are opting for the newer technologies as their standards, and providing backward compatibility for older motherboard types.

The ATX Connector is native 24-pin. Unlike other power supplies, it doesn't have a 4-pin block which can be snapped off for backwards compatibility with older motherboards. Users of the older 20-Pin ATX motherboards will have to purchase a converter in order to use this power supply.

The Zeus has no shortage of connectors. With 7 Molex connectors and 4 SATA connectors this Power Supply is ideal for those with lots of hard disks and optical drives.

* The 8-Pin EPS12v connector can be converted to a 4-Pin ATX/P412v connector by means of an included converter.
** An additional 2 PCI-E connectors have been included in the accessories box.

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Looking Inside

"Built like a tank" is one way to describe this unit. Never before have I had so much trouble taking a Power Supply apart.
I was slightly concerned that when I finally managed to get it in pieces, I wouldn't be able to put it back together again to perform the testing!

Unlike traditional PSU's, the Zeus makes full use of the PSU casing, screwing full sized circuit boards on to both the top and bottom. This of course means they need to fully protect the circuit boards from touching the casing. They have done this by screwing large plastic sheets over the circuits (top left picture).

No expense has been spared when selecting a fan to cool the unit. A Sanyo Denki San Cooler 80mm fan has been installed which pushes a healthy 42cfm at a reasonable 34dBA when running at 12v.

Its clear to see that the Power Supply has been constructed with only the highest quality components, which of course has made it quite hard for Silverstone to fit everything into a reasonable sized case.

Everything is tidily arranged and the two boards can be fully disconnected from each other, which makes it easier to work on - not that you'd ever need to ;).

I was disappointed to see that the Zeus 750w didn't have any way of adjusting the voltages from outside the PSU (like the Strider 600w). The only potentiometer (pot) I could find inside the unit is shown above.

Unfortunately I was unable to test whether this pot made any difference to the voltages, as the unit is far too awkward to disassemble and reassemble. Maybe Silverstone will be able to confirm if this potentiometer has any effect on voltages.

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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 is capable of placing loads on the following rails:

+3.3v - 20a Load
+5.0v - 20a Load
+12v1 - 10a Load
+12v2 - 10a Load
+12v3 - 10a Load
+12v4 - 10a Load
(or 40a on a single +12v rail)

The results are collected from a Mastech MAS-345 Multimeter which logs its readings via RS232 to a PC.

Good results from both the +3.3v and +5v rails here. Neither dropped by any significant amount and both remained well within ATX specifications. These results should make those who enjoy pumping lots of voltage through their RAM very happy, as major drops in voltage on these rails (dependant on motherboard used) can cause serious RAM stability issues.

I was nothing short of stunned by the results from the +12v rails. So much so that I actually tested my equipment on another Power Supply to ensure it was working correctly.

None of the 4 rails dropped below 12.00v and most only experienced a drop of 0.02v with a 10a load applied to each of the rails - that is simply AMAZING.

Silverstone have clearly spent a lot of time and effort ensuring that the Zeus is of the highest quality, and in my opinion, this places the unit directly in fierce competition with the likes of PCP&C and Zippy.

Noise Testing

At present Overclock3D doesn't have the correct equipment to reproduce accurate stats on the dBA output, so for the moment you will have to rely on my ear :)

The Zeus is not a quiet Power Supply - I will say that now. From what I could tell the installed fan appears to run at 100% even when idle. As stated on the previous pages, the Zeus uses a Sanyo Denki San Cooler 80mm fan that pushes 42cfm at 34dBA.

Having listened to various fans, I would say that the noise output is closer to 30dBA. The installed fan does not make any mechanical or high pitched noises, just the noise of air turbulence which is to be expected.

Check back on this review at a later date for professional noise level testing results.

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Conclusion

The Silverstone Zeus 750w Power Supply is a monster. It passed our PSU Stress Tests with flying colours where many other manufacturers have failed miserably in the past.

The rail stability, particularly on the +12v rails was outstanding, much better than I would have ever expected of any Power Supply.

With Matt Black paint, this Power Supply is as plain as they come so 'bling' seekers should look elsewhere. However, this isn't to say you cant respray the unit in some funky metallic paint and sleeve the cables in UV braiding ;)

From what I've heard, this is Silverstone's first batch of the ST75ZF. Future batches will include an all black fan grill, all cables sleeved, and four dedicated PCI Express power connectors!

With a retail price expected to be around 158EUR + VAT, this is a great value piece of kit at a very competitive price. Now there's no reason for anyone not to have a top quality PSU in their PC!

Pro's
Outstanding performance.
Competitive pricing.
Excellent build quality.
Enough connectors for any system.
Cables to run 4x PCI-E cards.

Con's
May not fit all cases (check before buying).
Not all cables are sleeved.
No adjustable potentiometers (that I could find).
May be a little too noisy for some.

Editors Choice

Thanks to Silverstone for providing this unit for review :)

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