Five Power Supplies Compared

EconolineCrush writes "Tech Report has done up a comparison of five high-end power supplies that looks at actual voltage levels and AC ripple content. The article also takes a look at environmental factors like noise levels and each power supply's impact on system temperatures. Think power supplies with like wattages are created equal? Think again."

Comments

So what difference does a good power supply make?

[jrockway]

Is there something that these power supplies contribute towards overall system stability that "cheap" ones don't? Are they really worth the money?

The article was very good at measuring everything measurable about the power supplies, but didn't answer the question "Why would I want one of these?". So why would I?

Power supplies

[stratjakt]

I seriously tire of "tech" reviews on stuff like power supplies, roll out keyboard drawers, cd holders, etc... This is the third "tech" article about power supplies I've seen here in a year.

Here's all you need to know:

Pick up two of the same rating, different brands. The heavier one is better - more windings on the coils and better components.

The end.

older tests :

[Anonymous Coward]

http://www.tomshardware.com/howto/20021021/index.h tml

21 power supply tested here :)

Re:So what difference does a good power supply mak

[neodymium]

Good PSUs contribute a lot towards system stability. For example, a moving head in the HDD causes current transients (so does a CPU switching between normal operation and power saving mode). Bad PSUs have huge voltage drops during these transients, good PSUs can buffer them quite well. These transients can cause anything between nothing and total system crash.

Also, the ability to filter noise out of the AC helps with stability...

Ahh.... the beauty of power supplies

[archeopterix]

The funniest quote from the article:

"Aesthetically, there's not much to see with the SilentX; it looks like, well, a power supply."

From the article.

[Prince_Ali]

Would you dare put cheap gas in a Porsche? Of course not, yet I continue to see enthusiasts putting cheap power into their high-end PCs.

Where can I find this cheap gas now?

Re:So what difference does a good power supply mak

[saskwach]

In a cheap power supply, you can get inconsistent voltages, crazy transients, crosstalk, and if the power demand from one line goes up it can drop the wattage/voltage on the other lines. Cheap power supplies are also frequently noisier (sound too) than high end ones and run less efficiently (read: hot) than better designed, more expensive power supplies. Think about it: your computer operates because of well controlled voltages. If your voltage drops by 2V, some transistors will go into their linear range and cause crazy crazy crap to happen.

Re:So what difference does a good power supply mak

[Tmack]

Having worked at a computer repair shop, I can assure you, YES there is a BIG difference between cheap PS's and quality ones. Cheap ones will last only a few months on any newer system, they might last a few years on older ones. Blown PS's was one of the most frequent repair jobs, and anytime someone requested the cheapest part to replace it with, I knew I would see them in a few weeks. They also affect System stability, if the PS cant put out the power the computer needs, it will crash (and the PS will burn itself up sooner as well). Got frequent blue-screens/sig11's and cant find anything wrong? Change your PS to a better one, there's a good chance thats the cause. Go to a local computer shop and pick up a cheap one in one hand and a good one in another, you will feel the difference. I always recommend Sparkle (there are some re-branded ones made by sparkle, will have SP in the model #) and HEC, and although I havent RTF yet, I would bet one of those is at the top, and the other is close to it.

Another thing to consider when buying a case.. the PS they put in cases are the CHEAP kind, unless they specify what kind it is, I generally expect to replace it within a year. A few years ago I had one of the dual socket370 BP-6 boards, it refused to boot on the PS I had that came with my case (Enlight none the less). I swapped it to a sparkle 300watt and have had no probs since.

This was also recently covered by Tom's Hardware, and earlier by a few other sites. The sparkle and HEC normally blow away the rest, with their 250w beating the specs for most 300+w, and even being able to hold 300w operation themselves.
just my $.02

Tm

Re:So what difference does a good power supply mak

[jfw25]

a moving head in the HDD causes current transients

Indeed, I was disappointed that their testing regime didn't include any disk seek stress tests; a test which forced two disks (or more) to simultaneously seek from track 0 to track N would would exercise the PSUs' transient capacity really well.

Many years ago, a development system I was using had a cabinet with four disks in it. Every once in a while, during parallel makes, all four disks would spin down simultaneously. Eventually, we discovered that if all four drives were told to seek simultaneously (easy to do on a SCSI bus), the resultant load on the 12V line would pull it out of spec, the power supply would shut down, and the disks would spin down (releasing the overload and allowing the power supply to come back up, hiding the evidence). Since this box was a kludge, we "solved" it with a big, fat capacitor on the 12V line (next to the drives) to handle transients. (Which probably reduced the power supply's lifetime due to power up transients, but who powers down development systems?)

Modern disks do draw less transient current during seeks, so this isn't quite the issue it used to be, but it is still a source of stress they ought to have checked.