80 Plus hits Retail: Silverstone's Element ST50EF-Plus

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September 24, 2006 by Devon Cooke

Silverstone Element ST50EF-Plus
80-Plus Certified 500W ATX12V 2.2 Power Supply
Market Price

The 80 Plus certification program for high efficiency power supplies has been well covered by SPCR, and the name should be familiar to most of our regular readers. However, actually buying an 80 Plus power supply is not easy. The reason for this is simple: The 80 Plus rebates are available only to system integrators who use approved power supplies in complete PCs. Few 80 Plus models are available in retail channels — the program simply isn't targeted at the retail market.

However, consumer recognition that 80 Plus certification is a sign of a good power supply is beginning to change that. FSP's fanless Zen power supply was the first retail package model to be approved, but now there are quite a few on the 80 Plus list. Silverstone has two 80 Plus approved models, 400W and 500W versions in their Element line. These are 120mm fan power supplies. The test sample's 500W capacity should be enough to satisfy those who don't think that 300W is enough.

The "Plus" in the name and the 80 Plus logo differentiate it from the regular 500W Element.

The Element comes with ATX and AUX adapters instead of the more common "split" connectors.

Feature Highlights of the Silverstone Element Plus (from SilverStone's web site)
Shorter cables designed for SFF and Micro-ATX cases
Not on our sample. Silverstone makes a special version with shorter cables. Details here.
Efficiency over 80% (20% to 100% loading) 80 Plus certification gives this claim a lot more weight than usual.
Dual +12V rails for advanced systems
We're a little sick of seeing this feature advertised as "special". It's a requirement of ATX12V 2.x, and it seems to cause more problems than it solves.
Dual PCI-E connectors (support SLI or CrossFire)
Essential (and very common) for a recent high end power supply.
Silent running 120mm fan
Silent is a dangerous word to use. We'll settle for quiet.
Support for ATX12V 2.2 Support for the latest standard.
Active PFC
Allows smaller UPS units to be used and may save some users money in utility bills.

AC Input
90V ~ 264V @ 47Hz ~ 63Hz (Auto Range)
DC Output
Minimum Output Current
Maximum Output Current

Maximum Combined

432W (36A)

As we would expect of a 500W power supply, all of the voltage rails have generous capacities. Both +12V rails are specified at 18A, and the combined rating should allow both to supply that amount of power simultaneously.

The minimum output ratings are of more concern. Our investigation of power distribution across the various voltage rails did not reveal any systems that would trigger the minimum load protection on the +3.3V and +5V rails, but the +12V rails are another matter. Of the six systems we tested, four drew less than 1.0A on one of the +12V rails at idle.

We saw a similar trend when we examined CPU power consumption in detail last April: Of 15 systems examined, 10 drew less than 1.0A from the +12V2 rail. These included several mobile processors and every single AMD chip we looked at. In fact, the only systems that required more than 1.0A at idle used Intel's now-obsolete P4 architecture. With the release of Intel's Core 2 Duo chips, it may not be unrealistic to say that just about every new system will run afoul of the 1.0A minimum load at some point.

So, what to make of this conflict between Silverstone's specifications and real systems? It is unlikely that Silverstone has released a product that will not work with the majority of systems, so it seems logical to treat the minimum load specifications as wrong. However, regular (and / or cautious) readers should be aware that some high efficiency power supplies have had stability issues for exactly this reason.

There is no guarantee that the Element will not run into any compatibility issues in this time of transitions in CPUs and motherboards, but we can say that the Element had no issues running with no load at all, which means that the minimum load requirements are not as strict as they are specified.

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