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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."
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.
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Before I read the article my guess was that Antec would win...and I was right. From the low end to the high end these guys have got their stuff together.
Most of the cases we buy come with Enlight power supplies (they are Enlight cases after all for the most part). Although these Enlight PSes seem to be ok, I always replace them with a nice quiet reliable Antec when they are going home to me or to my family. I also recommend putting an Antec PS in to customers who buy the biggest, baddest gaming PCs.
The simple fact of the matter is though, that most folks don't really need a 550 watt PS. A 350 watt PS will more than handle the load of most average consumer PCs. I do dread opening up an e-Machine or various other "value" (aka cheap ass P.O.S) PC and seeing a 130 watt PS running a P4 CPU. *shudder*
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While all of these look good and they all have some pretty spiffy specs, it would have been nice to have seen some reliability test scores in there. A flaky power supply is a hard thing to track sometimes, and knowing which ones have the best chance of running reliably for the longest time period would be handy information, especially for those of us who have fought with bad power supplies at one point or another in the past.
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I've had so many powersupplies dying on me that it's not even funny. What I want is a PSU that delivers the promised effect, for at least three years. That would be the day.
Might be hard to benchmark that, so anybody got any tips for brands?
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It is strange that there are hardly any truly silent powersupplies, when there is almost no laptop with a powersupply that makes noise..
If powersupply manufacturers simply take out the heat generating part so that you can have it well ventilated and only let the dc wires go into the case, then the completely silent pc would be so much closer.
CC
You've got to be trolling. On the off chance that you aren't:
/. intro noted case noise and heat output into the case.
The article started right off by saying that system stability can be affect, that the stability of voltage levels and the amount of electrical noise varies greatly. It also noted that the power supplies distribute their power differently among the various output voltages The
The effects on the CPU, chipset and RAM of electrical noise and/or 'brownouts' of voltage dropping below specs should be obvious. I've seen several systems go instable because the 5vsb line, or some voltage branch like the USB line couldn't drive the attached components. What good is having 200 extra watts you don't need at one voltage, if the PS goes flaky at full output and real usage on another? A lot of power supplies that do fine (or almost fine) on a bench or at 50% of their rated current draw in the real world will flake out occassionally at 85%. A few milliseconds of flaking out ever several hours can turn a dream machine into a nightmare.
Hook an oscilloscope to distal power traces on the motherboard (not near the power supply, and depending on your supply, you can see some pretty ugly stuff as peripherals/cards switch on/off. Sure, a good motherboard should have plenty of well placed filter caps, but on a fully loaded system, you can *see* how adequate they sometimes aren't, if the power supply doesn't supply great power in he first place. It's possible to design very rugged and tolerant motherboards (e.g. military), but in the consumer market, price competition is so tight that boards are often revised in mid-production to save one or two caps.
I'm not saying top-of-the line is always best, but bottom of the line is pretty much asking for trouble down the line. Most people 'add and test' when they build (or expand a system with use), but the culprit may not be the card you just added; it could be the power supply you 'vetted' up front.
I paid the price for using a cheap PSU.
The damned thing blew up (went bang, magic smoke came out). When I fitted a new PSU, I found that when it went, it had taken out the motherboard, graphics card, both hard drives and CD-RW drive. The only survivors were the network card, DVD-ROM, keyboard and mouse. The fuse in the PSU didn't even blow.
Meanwhile, the adjacent Sun Ultra 5, Dell PC, printer and other kit carried on running as it always has - so I doubt it was a surge in the mains power.
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Well, I have found PSU problems. And the ulgy thing about it is that the PSU is the last thing I would have thought...
A couple of years ago I put together a decent system, TB 1GHz, 256MB DDR, ECS k7s5a mobo, etc. And a crappy tower/psu cuz I spent too much so I cut some corners on case/keyboard/mouse/etc. BIG mistake.
I started having problems with the computer. Random crashes and all. Damn, I think. Somebody suggests the memory is faulty. So I roll out memtest86, and sure enough, both memory modules are faulty! On a hunch, I try them on another computer, and they pass ok. So, the CPU must be fucked up. On another system, the CPU passes the test. So it must be the frigging mainboard. Someone suggests I try a different PSU, since the Athlons are known for their watt gluttony. Put in a new PSU, a bigger and decent-er one, and all problems evaporate. No more memtest fails, no more freezing, nada.
Yeah, every 10 fillups or so I put the high-octane in, that's more than enough to burn off any residue in the engine. You get the exact same advantage as if you'd used it every time.
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Power supply unit (PSU) in modern PC is much more complex than what you think. Also, switching PSUs can be designed in so many different ways with so many different parameters in mind that simply refering to the weigth of the iron in the coil is meaningless. About the compoenents, I don't think that better componenets should necessarily weight more (why should a better MOSFET weight more than the other one??) Generally speaking, as the CPUs are more power hungry today, Graphic cards consume so much power that they need a dedicated connection to the PSU besides what they get from the AGP bus, modern HDDs consum so much (and get so hot) and even RAMs in high-speed systems are power hungry, exceeding the classical 300W is nothing strange, considering the fact that you always need a margin for the safety (usually 85% of the rated value) and place for future exapnsion. And did you know that even in 300W class, may of the cheap PSUs can't even devliver beyound 250W withouth a significant drop in output voltages? A good, high power PSU is really a beast to design....
I'm an MIS guy for a small company (10 people, 20 PCs -- go figure...) and I always look at PC power and cooling supplies as well as other brands when I'm building machines. I think they make great server supplies or swap in replacements for older machines at the very least.
I have also used those guys for obscure CPU cooling fan options (try to find a quality replacement CPU fan for a Pentium Pro 200)! They stopped stocking them, but offered to make one up for a very reasonable cost -- I went with a different solution, but they were quite helpful. I have purchased several CPU fans from them and none have yet died.
I usually go with Antec power supllies for new workstations because, in addition to running well, they come standard in good Antec cases that I'd want for a workstation anyway.
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That's true. The hdd motor and head positioning is usually running on the 12V supply and its current profile is on/off at fairly high frequency.
We used to estimate power supply quality by weight. The heavier, the better, since it meant they had more iron. Bigger transformers = better magnetic storage = better voltage stability. Now the switching frequencies are high enough that you don't need big iron cores. But you do need a switching frequency that is a lot higher than the load current frequency. Otherwise the 12V won't be stable. Not that they will tell you the switching frequency in a spec.
I don't know if you'd want one of these top-of-the-line power supplies, but you definitely want a decent one.
About three years ago I bought a case without checking the power supply in it and after about a month of operation my mainboard died. I blamed the mobo (it was also a cheap brand), and replaced it with a really nice one. That one lasted about a year, but was really flaky the whole time, especially the onboard Promise ATA100 IDE controller which had so many errors that I stopped using it. When I decided to buy a new machine, I bought better stuff but I (foolishly) replaced the mobo in that system yet again and gave the thing to my wife. Where I'd seen minor instability and annoying failures under Linux, she saw daily bluescreens with Win2K. Finally I bought her a new power supply and all of the problems went away (well, she's still running Windows, but I'm working on that ;-) ).
So, at the end of it all, I'd say the $20 I saved on that cheap power supply cost me two motherboards.
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I just scanned the article, but I saw no mention of testing for line regulation. Maybe I'm just old school, but that used to be an important factor. Oh yeah, just thought of another one. Home users might be interested in knowing just how much noise that power supply is injecting back into your mains voltage. Switching power supplies are noisy little beasts.
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.
Well lets see, I had one of those cheap no name powersupplies in my last system. One night it blew up. That in itself was pretty cool, had fire and shit shooting out the back of the case, smoke coming out all the holes. Now for the uncool part, every thing in the system was toasted. About 1500 bucks worth of system up in smoke.
I guess it could happen with any powersupply but in this Beast I bought the one they recommended last year.
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Here's one easy thing that you can do to minimize the impact a power supply will have on the internal temperature of your case...
You'll notice on most power supplies that there is a fan venting heat INTO the case. An easy solution is to reverse the fan(s) in your power supply so that they pull air from inside the case and vent it out the back. This is especially handy when incorporated with a case fan in the front of the chassis that moves cool air into the case. This establishes a nice flow of cool in the front and warm out the back.
Reversing the power supply fans is usually one of the first mods I make to my PCs when setting up the cooling system.
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It is unfortunate Seasonic was not included in this comparison. This review explains how the Seasonic Super Silencer 400 is cool and quiet, a true 78% efficient PSU with Active PF.