SilverStone Zeus ZU1200M (1200W)
SilverStone markets its Zeus series as industrial class solutions. Let’s see in what aspects they differ from the Strider series.
The specific interior design of this PSU can be seen even without taking its cover off: the electronics reside on two PCBs facing each other. Where is the cooling fan then? This component layout makes it impossible to install a 120mm fan whereas a classic 80mm fan is nowhere to be seen at the front grid.
The answer is simple: the fan is at the back. A PSU is actually a metallic box with vent holes in its two butt-ends, so there is no difference between the two possible positions of the fan. The air will anyway have to go through the entire interior along the heatsinks.
As opposed to the Strider’s series, the PSU’s cables are fixed. The interior design and cooling system do not allow to implement detachable cables: there is no place to fit the connectors in.
The Zeus ZU1200M is equipped with the following cables:
- Mainboard cable with a 24-pin connector (55cm)
- CPU cable with a 4+4-pin connector (76cm)
- CPU cable with an 8-pin connector (75cm)
- Two graphics card cables with one 6+2-pin and one 6-pin connector on each (56+15cm)
- Two graphics card cables with one 6-pin connector on each (56cm)
- Two cables with three SATA power plugs on each (51+25+25cm)
- Two cables with three Molex connectors and one floppy-drive plug on each (56+25+25+14cm)
It is good that the cables are long. The selection of connectors is rather too modest. You can connect only six SATA drives to this PSU, which is too few for a 1000W model. And there are only two 6+2-pin connectors for graphics cards in the three pairs (they should be counted in pairs since modern graphics cards are powered by two connectors).
There are indeed two PCBs, facing each other, in this power supply. This is an unusual component layout as it is rather too complex and expensive. The choice of cooling fans is limited to 80mm models and low-profile components have to be used: capacitors, transformers and heatsinks of each PCB have only half the total height of the PSU.
The first PCB is about high-voltage circuitry: a filter, an input rectifier, active PFC.
The second PCB carries a power transformer, rectifiers, smoothing capacitors and secondary DC-DC converters. Despite the high wattage of this PSU, it has only one transformer that yields one voltage, +12V. The +5V and +3.3V voltages are produced from +12V by means of dedicated DC-DC converters located on small individual cards (you can see them in the top of the photo).
SilverStone tried to conceal the name of the real manufacturer but didn’t do that carefully enough. You can read the words “Impervio Electronics” through the smudge of black paint on the PCBs. This is the name of a Taiwanese company that was founded in 2006 and develops top-end PSUs with high wattage, hot swap feature, etc. By the way, Enermax bought a 75% share of Impervio Electronics in May 2009.
The specs are typical for this product class except that the +12V rail is split into six “virtual” output lines with a load capacity of 17A (204W) each. In such high-wattage PSUs some of the lines usually have a load capacity of about 25A because today’s dual-processor graphics cards can consume over 200W under load, which is more than those 17 amperes.
The user manual says that the individual current limitations for each separate line can be just turned off. However, the appropriate switch is hidden under a sticker that reads “Warranty void if removed”.
This may be due to the small size or position of the switch near other components on the PCB. A careless movement with a screwdriver may damage the switch or the PCB. Of course, the manufacturer might have some other reason to hide it but as warranty becomes void after my tests anyway I risked and turned the splitting of the lines off. The PSU worked well then and I could test it on our testbed with two 46A instead of six 17A lines.
Together with an APC SmartUPS SC 620 this power supply worked at loads up to 340W and 320W when powered by the mains and batteries, respectively. They switched to the batteries without problems and the UPS was stable. Thus, this PSU should have no problems working with UPSes.
Output Voltage Stability
It looks like a family trait of all SilverStone power supplies that their +5V voltage bottoms out at high load. On the other hand, this voltage only goes out of the permissible limits at loads that can hardly occur in a modern computer whereas the +12V rail, which is loaded the most, is very stable, keeping its voltage within a 2% deflection.
Output Voltage Ripple
At full load the output voltage ripple on the +5V rail is as high as the permissible limit. On the +12V and +3.3V rails the voltage ripple is considerably lower than the limit.
The PSU is cooled by an 80x80x25mm fan from Sanyo Denki.
The fan speed depends directly on load and the PSU proves to be rather noisy even at 350W.
Unfortunately, the PSU would shut down due to overheat at a load of 1010W during this test. Later on, I read a document from the SilverStone website and learned that thermal sensors had been misconnected in one batch of Zeus power supplies. The user is supposed to open the PSU up and correct that. As I found the document after I had done my tests, I could not check this solution out in practice.
Efficiency and Power Factor
The efficiency is far from high, not reaching 85% even. It drops below 80% at full load.
The standby source is rated for a current up to 4A and copes with the job. Its output voltage is never lower than 4.9V.
I did not find the SilverStone Zeus ZU1200M to be any better than the other products from the same company. The quality of the Zeus is up to the promised industrial level, but the Strider is just as good. The consumer properties of the Zeus are not quite up to today’s requirements. It is too noisy and not very efficient.