Page 1:Brought To You By Granny’s Radio
Page 2:How A Switching Power Supply Works
Page 3:Efficiency, Efficiency, Efficiency!
Page 4:Of Power Factors, Apparent Power, And Effective Power
Page 5:How To Spot An Efficient PSU?
Page 6:Don't Get Burned: Safely Before Stinginess
Page 7:How To Determine Your Power Requirements
Page 8:The Power Window Is Important
Page 9:Example 1: The Office PC
Page 10:Example 2: Mid-Range Gaming PC
Page 11:Example 3: The Enthusiast’s System
Page 12:If You Don't Like Our Advice, Buy A Fire Extinguisher
Example 2: Mid-Range Gaming PC
Test Case 2: The Mid-Range PC
Again, let’s begin by taking a look at our mid-range build.
|CPU||AMD Athlon X4 640 |
|RAM||4 x 2 GB DDR3 Kingston HyperX|
|Graphics||HIS Radeon HD 6870|
|Hard Drive||1 x 1 TB Western Digital Caviar Blue|
|Optical Drive||DVD burner|
|External Devices||USB hard drive, mouse, keyboard|
|Power Draw, Idle||78 W|
|Power Draw, Normal Load||126 W|
|Power Draw, Full Load||332 W|
Next, we pick out some likely power supplies. Our choices are:
|Hardwaremania24||Standard ATX 420 W||none||$14 (€9.90)|
|LC-POWER||LC6350 Super Silent 350 W||none||$28 (€19.90)|
|Rasurbo||Real & Power RAP 350 W|| 80 PLUS||$49 (€35.00)|
|Super Flower ||Golden Green 450 W||80 PLUS Gold||$83 (€59.00)|
|Enermax|| Modu 82+ II ErP 425 W||80 PLUS Bronze||$113 (€80.00)|
Two PSUs Are Killed In Action
That brings us back to our charts. Sadly, two of our contenders didn’t survive this scenario. Then again, this was hardly a surprise. Remember what we said about the spec sticker on the one unit that claimed a lot more power than it could realistically supply? Yep, that was one of our casualties. More interesting than the fact that it died at all was the point at which it happened. See for yourself:
Rasurbo is able to retain its lead when the system is idle. But once the computer sees a normal usage pattern, Super Flower winds up ahead, albeit by a slim margin. Despite its much higher price, the Enermax unit places third so far. LC-Power and the cheap Hardwaremania24 PSU come in last.
Under full load, Enermax can finally advance to second place, coming in right behind Super Flower. Rasurbo’s Real & Power RAP 350 W is right up against its limit, which is borne out by the decreased efficiency. It really is just a bit underpowered for this build, which is why wouldn’t recommend this combination for extended use. Downgrading to a Radeon HD 6850 would probably alleviate that concern, though.
In order to let our two low-cost candidates compete here as well, we had to use some PCIe adapters so we could power the graphics card. LC Power’s so-called 350 W model died a sudden (albeit quiet) death, giving off a hiss and a picturesque little cloud. We decided not to continue testing the Hardwaremania24 model under load, since it began giving off a pungent odour when we started up Google Earth in our “normal load” scenario. We considered that warning enough and chose to protect the remaining hardware from imminent meltdown. We’re not exaggerating that danger, either. That particular model lacks any kind of protection mechanism beyond a very sluggish micro-fuse.
- Brought To You By Granny’s Radio
- How A Switching Power Supply Works
- Efficiency, Efficiency, Efficiency!
- Of Power Factors, Apparent Power, And Effective Power
- How To Spot An Efficient PSU?
- Don't Get Burned: Safely Before Stinginess
- How To Determine Your Power Requirements
- The Power Window Is Important
- Example 1: The Office PC
- Example 2: Mid-Range Gaming PC
- Example 3: The Enthusiast’s System
- If You Don't Like Our Advice, Buy A Fire Extinguisher