Tom's Hardware Compares Power Supplies

Some guy wrote in to say "Tom's Hardware Guide takes a hard look at power supplies to find out if we are getting what we paid for. The results of the testing were very surprising." Very useful to anyone who has built their own machine from scratch or burned out a cheap power supply.

Comments

Any article that has a flaming PSU is good.

[Prince_Ali]

I hope a few of those people who pay $400 for the latest and greatest video card and $15 for a power supply read this.

Missing Test Equipment

[CMiYC]

I don't think these were fair tests. I would have liked to seen some oscilloscope measurements of what the voltages/waveforms looked like under full load. Being that we expect our DC power supply to delivery a DC voltage, even a novice can tell a "bad" output from a "good" output. Take two power supplies for example. A 300W and a 500W supply. (For numbers sake, let's say they only deliver 5V to the load. No +12v, -12v, etc). If I max load the 300W supply and it is delivering a clean 5volts, that's a great supply. But if the 500W supply is spiking or has considerable noise with a 300W load, who cares if it runs up to 500W?

To me that's almost more important than if the supply shuts itself down or not. Which, by the way, is still a nice FEATURE.

Re:Missing Test Equipment

[mark_anderson]

CMiYC has an important point. There's a lot more to a power supply than simply providing lots of DC current. Tom's Hardware used a constant load. Computers, especially CPUs do not form a constant load. A cpu may increase its consumption by a factor of 10 almost instantaneously. This can happen everytime the scheduler goes from the idle loop to running a cpu intensive task. The motherboard regulation will absorb some of this, but not all. The PSU must be able to respond to these surges without significant ripple or spikes. This requires good capacitors, and may require tuning the switcher frequency to improve the response.

You get what you pay for

[Pedrito]

This applies particularly to power supplies. Sure, CPUs and memory, but the prices aren't nearly as fixed as they are for power supplies. Really, with power supplies, the price range doesn't vary much and the good ones tend to cost (though there are some decent ones for decent prices).

Before I came to my company, they bought a bunch of no-name PCs. There must have been a motherboard flaw that caused them to burn out power supplies and they kept replacing them with cheap supplies which couldn't handle whatever the motherboard was doing, and they would burn out too. Out of about 8 machines, I think we went through 14 power supplies in two years.

You'd always hear, "What's that burning smell?" "Did you check the back of your machine? I think that's smoke from your power supply."

I ALWAYS get a decent supply and have NEVER had problems, even when I lived in Mexico and had pretty questionable electricity.

Tomshardware

[Anonymous Coward]

A single floppy connector, as supplied by Engelking and Coba, is not enough. You will need at least two of these.

Haven't given them a thought in over a year. All their "reviews" tend to shine highly on the products that fit "their" personal views. I mean jesus, any place that thinks you should have 2 (two) floppy drive power connectors is a little behind the times. Most people don't even use 1 floppy, let alone 2. And for all you people who weren't aware, a reviewer is supposed to enter a situation unbiased. Tom's hasn't started a review unbiased in easily 2 years.

No PC Power and Cooling?

[LordNimon]

The only decent third-party manufacturer of power supplies that I (and I presume most people) have every heard of is PC Power and Cooling. It doesn't appear that this article covers any of their products. Am I missing something?

Only one of each tested

[f97tosc]

That is not a very large sample. I wonder how much specs vary between individual units of the same make and model.

In particular, it would not surprise me if there are unit-to-unit variations in noise and the power at which they give up.

Tor

PS Diagonistics?

[Masem]

I'm surprised that in this day and age, where your power supply is becoming one of the more critical components to keep track of (along with the CPU and GPU temperatures), that there's yet to be a way to monitor the performance of the PS with hardware/software monitors, short of wiring your own. That is, just like you can monitor temperatures and fan speeds with most modern mobos, the power supply is completely independant of this. Yes, it would require some standardization of how that info is sent and a plug on the mobo (most likely situated near where most USB/KB/M cutouts are as to avoid a 20ft wire to get it to the northbridge site), but it would seem to me to be really useful information to determine the PS health beyond the current hope-n-pray methods...

Could have done better...

[KC7GR]

For my part, I would have liked to have seen THG use a true electronic load for their testing. Something from Transistor Devices 'Dynaload' line would, I think, have been a much more accurate (if more expensive) choice than a box full of power resistors.

They should also have used a good O-scope to take a look at the power output waveforms while under load. I've seen a number of cases where a switching supply will look perfectly clean under low-to-medium loads, and then start to spike and freak out under higher loads. 'Tis a nasty thing to behold, and it can cause problems that can drive techs who don't know what to look for absolutely batty.

Also, others have mentioned that PC Power and Cooling was left out of the review for reasons unknown. I would guess that it was price. If so, all I can say is "How highly do you value your hardware?"

Clean and adequate power is the ONE factor that can cause more woes than any other. You can have the slickest quad-processor-super-Linux-cluster-RAID-whatever on the planet, and it won't do you one whit of good if you've got dirty power feeding it.

Re:Non-custom built power supplies poor?

[Tailhook]

It's a question of usage patterns and necessary capacity. The common Best Buy PC used in a typical manner does not tax a garden variety Chinese PSU enough to ruin it.

A SMP box with a Gig or more of RAM, used to compile kernels, run FPSs at high resolution, host a couple extra drives of various sorts, get frequently booted between multiple OSes (startup loads are extraordinary,) run benchmarks, and basically do a bunch of other crap, will need a LOT more power. I fried an Antec 300W PSU in 3 months like this. Give yourself a fright and watch the case temperature during a FreeBSD "makeworld" sometime.

Tom's caters to people that push high end hardware to it's limit. You're basically reading hotrod magazine and wondering what's wrong with your Accord.

How About Using LESS POWER?

[ink]

Am I the only person who is sick of computers requiring such obscene amounts of power? Newer machines have fscking radiators on them for $DIETY's sake; what's next? A heat-pump that sits outside my house to keep the environment nice and warm? In 1995, 250W was a nice, big power supply. Then, 300W, and now 500W comes along -- other consumer electronics are becomming more efficient (monitors, televisions, refridgerators, air conditioners, etc.), but computers just keep wasting more and more power.