Picking The Right Power Supply: What You Should Know

Example 1: The Office PC

Test Case 1: Office PC

Here’s a look at our standard office PC.

Office PC

Office PC

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Specifications

• CPU

  Intel Core 2 Duo E8400

• Motherboard

  Abit I-N73H

• RAM

  2x 2GB DDR2 Kingston Value RAM

• Graphics

  On-board

• Hard Drive

  1x 500GB Western Digital Caviar Blue

• Optical Drive

  DVD burner

• External Devices

  Mouse, Keyboard

• Power Draw, Idle

  53 W

• Power Draw, Normal Load

  90 W

• Power Draw, Full Load

  122 W

• Power Meter

  Energy Logger 4000 (Conrad Electronic) • Long-term measurements • Monitoring • Consumption measured up to 1.2 kW

Our goal is to find a suitable power supply for it. We’ll have to ask your forgiveness here, as this article originated with our German team. While some of the power supplies used by our colleagues may not be available in the U.S., they still serve to illustrate the point quite well.

Also, we were hoping to use Huntkey’s Jumper 300W 80 PLUS Gold as our standard. Sadly, the review sample we were promised got stuck somewhere between China and German customs and didn’t make it to the lab in time. That’s why Super Flower's 450W Golden Green is taking its place, despite being a bit on the beefy side for what we need. So, without further ado, here are our candidates:

Big Charts For Our Smallest System

Now for the big reveal. How do our various contenders stack up? Well, have a look for yourself. There are certainly some pronounced differences:

Nineteen watts separate the best and worst power supplies at idle, with be quiet! and Rasurbo taking the top spots. The Gold-certified Super Flower model places third, with the two cheapest PSUs landing last.

That ranking doesn’t change much when we look at a normal usage scenario, where the difference between first and last place shrinks to 11W. However, Rasurbo and be quiet! trade places, while the rest of the field stays unchanged.

Under load, the delta between our top performer and the worst offender increases to 14W, with Super Flower's submission taking the lead ahead of Rasurbo and be quiet!. Meanwhile, the super-cheap Hardwaremania24 PSU's efficiency curve starts to fall off again, exposing the component as a rebadged 250W model. If you want to try for 300W using a sub-par piece of hardware like that, keep a fire extinguisher handy.

Conclusion

In all three scenarios, the 80 PLUS-certified models take the top spots. Interestingly, the Gold-rated Super Flower PSU only takes first under a full load. As such, its higher price doesn't really seem worthwhile. Then again, it does get penalized somewhat by being the highest-capacity model in this group. Super Flower's big advantage is a semi-passive cooling mode. Under these loads, the fans don't spin up at all, making the Golden Green 450 W an interesting choice for quiet PCs.