Why the need for >$13 PSU's?

[Shinare]

There are $13 shipped 400W PSU's out there and there are ~$100 400W PSU's out there.

I really would like a good (good meaning no fanboy posts) discussion here as to why one needs to spend the money on "high quality" PSU's over the cheap cheap X brand flavors.

I have, from the time I started building PC's 15 years ago, been in the "if it works, its good" camp for most PC components other than CPU/mobo. I have had people TELL me that Tt, Sparkle, Antec, (insert your favorite "high end" PSU here), etc are better than the trash you can get for $15.

But none have a compelling reason other than "they supply 'cleaner power'". I am prepared to accept that answer with a little explanation with forethought and examples to back it up and WHY this is important. Usually tho, the explanation I get is just "I have heard" or "I bought a $15 PSU and it fried my system" (which has never happened to me) or "Why trust your $1000 computer components to be powered by a $15 PSU?" but spending more on a PSU just because you spent more on other components isn't a very good reason either.

Why is "Cleaner Power" even a concern. I thought that was what the voltage regulators on the mobo were for? Why is a heavier PSU better? Just because it has a bigger HS on it?

The whole topic has been brought up in my world only because I have recently upgraded to an A64 Winchester 3000+ that I plan to OC. I currently have a $7 350W PSU that SEEMS to be handling the load fine but has a 13w +12v rail and people over and over tell me you need 20a to OC an A64. So I need to upgrade. Basically that means I need a 500W psu and I would rather not spend $80 if I don't need to.

All help and discussion is appreciated.

 

[JasonandBecky]

I have lost numerous parts due to crappy power supplies.

motherboards, ram, modems...

Never again.


Add to the fact that a very good power supply simply lasts longer, has a real warrenty, is more stable for overclocking, can provide more headroom for powerhungry systems of today.

 

[imported_Computer MAn]

Because cheap PSU's can not hold their power under load, have a tendency to blow up, and many other reasons.

 

[dullard]

Old, but very useful article.

Summary: Power supply labels lie. The power supply can often provide far less power than what the label states. This is not a good thing if you need the power. Damage to the power supply and other components can and does happen.

For example, in that article, the Task 930TX power supply claimed 300 W of power. That should be plenty to run most computers. Yet in testing it only was capable of handling 204 W of power. That will fail in any computer with a high end CPU and video card.

Overclocking will magnify power supply problems. If you were on the edge of it failing, overclocking just sucks up that much more juice. Even a temporary spike down in power can cause lockups or other undesirealbe outcomes. In the world of power supplies: more mass = more uniform power. There is no real way around that. Also, more mass = more cost. Still no way around that.

You may luck out with a cheap power supply. It may perform quite well in the specs. I've designed a machine that requires 24 V DC power. I've gon through many cheap DC power supplies and many work. But 1/10 won't work at all in my machine even if the other 90% of the same make and same model do work. I put a voltometer on and the power is consistantly read at 24V (plus or minus a little bit). What is the difference? Tiny spikes up or down can severely affect sensitive equipment. Think of the thermistors in your computer and what they do (ie what they protect), they require a steady DC voltage.

 

[asm0deus]

i've heard of people's expensive power supplies blowing stuff up too! just get what you can afford and stick with the best manufacturer's you know of.

 

[LifeStealer]

If you skimp anywhere it better not be the PSU. But who are we to say, go ahead and buy a cheap one and when your first three video cards and ram burn out drop us a line.

You don't need a 500w PSU unless you're planning on SLI IMHO. A nice strong 420w with good 12v rails would be fine.

 

[wisdomtooth]

Data corruption and computer crashes can also be attributed to cheap power supplies, when the electrical power wanes under load or fluctuates.

YMMV of course..

My personal reason for going with a more expensive power supply? My ears can't take the noise from the cheap fans anymore-- I hate computers that sound like aircraft-testing wind tunnels. So I picked up a ultraquiet $60 Seasonic.

 

[jterrell]

At one point pc's used only 60 to 70 watts of power so all the psu's were overpowered for their needed tasks. Crappy psus's rated at 250 watts still consistently put out more than 150 so the pc performance didn't suffer.

BUT since the p4/socket a era psu's have begun to reach points where the lower end models no longer power things properly. A 400 watt powmax may only get you 230 watts at times and that can cause you to not only see crap peformance including reboots but also to fry your cpu or mobo. I know because this happened less than a month ago to my parent's pc.

I gave her my 80 dollar fortron psu but she still had to buy her own mobo which meant 75 bucks she spent even with a free psu. She coulda gotten a decent psu for 50 bucks and never had the issues she did. But now with the upgraded psu her system runs faster according to her, never locks up and doesn't randomly reboot.

With a new gen pc I would buy a psu that is at least half the cost of your processor and at least the same cost as your mobo because if you do not chances are you will be buying one or both of those items again.

Rest assured, one fried pc is all it takes to swear by high quality psus
Its a pain in the behind to test each component(assuming you do not have a full test bench set up) to find which ones aren't working.

 

[nick1985]

do you buy a porsche and put regular in it? hell no, it needs premium. just the same with computers, you get an awesome rig and give it a sh!tty power supply just to save a buck.

the power supply is THE MOST important part of your computer. a bad one, and you can kiss everything hooked up to it good bye. if you are willing to chance it, be my guest.

 

[Sonic587]

Originally posted by: Shinare
There are $13 shipped 400W PSU's out there and there are ~$100 400W PSU's out there.

I really would like a good (good meaning no fanboy posts) discussion here as to why one needs to spend the money on "high quality" PSU's over the cheap cheap X brand flavors.

I have, from the time I started building PC's 15 years ago, been in the "if it works, its good" camp for most PC components other than CPU/mobo. I have had people TELL me that Tt, Sparkle, Antec, (insert your favorite "high end" PSU here), etc are better than the trash you can get for $15.

But none have a compelling reason other than "they supply 'cleaner power'". I am prepared to accept that answer with a little explanation with forethought and examples to back it up and WHY this is important. Usually tho, the explanation I get is just "I have heard" or "I bought a $15 PSU and it fried my system" (which has never happened to me) or "Why trust your $1000 computer components to be powered by a $15 PSU?" but spending more on a PSU just because you spent more on other components isn't a very good reason either.

Why is "Cleaner Power" even a concern. I thought that was what the voltage regulators on the mobo were for? Why is a heavier PSU better? Just because it has a bigger HS on it?

It all comes down to "You get what you pay for."

Here's some good info on the snake oil generic PSU manufacturers use (from SPCR):

POWER SHMOWER
or How PSU Power Ratings Mean Almost Nothing

A frustrating fact about PSUs is that there does not appear to be a stringent or regulated standard for reporting, advertising and labeling rated power. This is despite the existence of standards like ATX2.03 or Intel ATX12V.

There are well-established standards for measuring and rating HDD capacity, an engine's horsepower, or the heat generated by a furnace... but not one for how much power a PSU can deliver. There are so many cases of people with "450W" PSUs having power stability issues running a system that can't possoibly draw more than 150W. And "300W" units that keep running where the "450W" units are faltering.

It's not just about bad PSUs vs better ones. It's a dumb situation caused by uncontrolled marketing competition. Real regulation would bring PSUs out of snake oil territory and into a more sensible consumer-friendly terrain.

There are many ways PSU makers fudge to make their units seem more powerful.

1) Out and out lying. You add up the power on all the lines in many PSUs and they fall short of the rated power by 10, 20 30W or even more.

There are more sophisticated ways:

2) Limit the AC input voltage to a very narrow tolerance. The best PSUs are able to deliver their rated power given a decent range of AC input power, say 90~130V for a 120V unit. It's much more demanding to produce 300W w/90VAC input than with 120VAC, so what some PSU makers will detail in their tech specs (usually not in their consumer brochures) is to specify 115-120VAC for input power. A PSU specified this way will not deliver full power if the AC voltage sags, if there is a brown-out. Surely it causes instability more often than a PSU rated to deliver full power with 90-130VAC.

3) Specify a low operating temperature for rated output. This is quite common, but again not often seen in consumer brochures, but rather tech spec sheets provided usually only on demand by engineers or corp buyers. A typical PSU operating temp statement is somthing like this:

0ºC ~25ºC for full rating of load, decrease to zero Watts O/P at 70ºC

Examine what that says. Full power (let's say 400W) is available when the unit is at 0ºC ~25ºC. Hmmm. Think about this.

Have you ever felt air blown out of a PSU in a PC running absolutely full tilt (which it would have to do to get anywhere near 400W output) that felt cool to the fingers? 25ºC airflow would feel exactly that: Cool, given that normal body temperature is 37 °C.

So this PSU cannot deliver full rated power when its temperature goes over 25ºC. OK, what happens to the max power output capacity above that temp? It decreases gradually so that by the time the PSU temp reaches 70ºC, the PSU cannot deliver any power at all. So if you assume that this power drop as temp rises is linear, then max power capacity will drop by ~9W for every degree over 25ºC.

Now having examined as many PSUs as I have over the last 2~3 years, I have to say there's not a single PSU in ANY PC I have ever used or examined that would not measure at least 30~35ºC almost anywhere inside the PSU under almost any kind of load. And if/when it is pushed, 45ºC is nothing at all, especially for or near hot running components like voltage regulators.

So let's say 40ºC is a fairly typical temp inside a PSU. This 400W rated unit would actually be able to deliver a max of just 220W at that temp. Hmmm. Interesting, isn't it? At 50ºC, the available power would drop to just 130W. No wonder some PSUs have 3 fans each capable of 50 cfm!!

Here's a simple fact: Really high quality PSUs are actually rated for full power output at as high as 40ºC. The trick is get a hold of the spec sheets that tell such information so you can compare apples to apples. Or ask.

Still want to go with a $7 PSU? I thought not.

The whole topic has been brought up in my world only because I have recently upgraded to an A64 Winchester 3000+ that I plan to OC. I currently have a $7 350W PSU that SEEMS to be handling the load fine but has a 13w +12v rail and people over and over tell me you need 20a to OC an A64. So I need to upgrade. Basically that means I need a 500W psu and I would rather not spend $80 if I don't need to.

All help and discussion is appreciated.

This is another PSU trap that people fall regularly fall into. Don't be fooled into thinking you need a 500W just because your generic 350W isn't cutting the mustard. QUALITY is MUCH more important than quantity. Unless you're going to be running a dual Opteron/SLI 6800U system, you're not going to be needing more than 400W for quite a while.

Why don't you list your specs here? There are plenty of good budget options for PSUs. You don't need to spend $100.

 

[Looney]

You've been 'building' computers for 15 years, yet you don't know how important the PS is? Personally, it's one of the most important piece of hardware in the computer. A crappy PS might not blow your videocard everytime, although there are chances of it ruining hardware, but just plain old stability. They can cause BSOD, random reboots, freezing, data corruption on HDD, and other things. And comparing totals watts to total watts isn't always right. I've seen high quality PS that are only 250, but they handle systems that a low quality 400watts couldn't do... why? because the actual rails are better and more consistent.

 

[kornphlake]

I was using a PC power supply to power a burn in rack just last week. We needed to run 36 devices that draw about 100 mA at 3.3 volts. I figured a ceap 250W power supply would handle the task given that the 3.3 V rail was rated at something like 13 amps and I only needed about 8 amps. What I found was that the powersupply would only provide a continuous current of about 3 amps. I could only run about a third of the devices I needed to on the burn in rack before the powersupply's thermal protection circuit would switch it off. Looking at the power with a scope you could see how the power supply could provide a current peak up to 13 amps but it's ability to continuously supply that much current was grossly overstated. Now imagine your processor that also runs off of the 3.3 volt rail, you are running an app that does a lot of processing, your processor is either going to be starving for current because a cheap supply can't give the current necessary or if the processor does somehow manage to suck all the juice out of the capacitors in the powersupply the machine will reboot, you'll be chasing hardware problems by swapping your mobo, processor, video card, memory, whatever you have on hand, when the real culprit is your $8 powersupply.

That said, I've never had an issue with my own machines running cheap power supplies, other than the fact that I have a history of killing computers after about 4 years, at which point an upgrade is expected anyway.

 

[Tostada]

I'm not one of the guys who says you absolutely must use Antec / Enermax PSUs. I've had absolutely no problems with cheap Apex cases that come with cheap 250W Allied PSUs, but that's just for cheap systems with one hard drive and a regular Athlon XP.

I have had PSU-related problems, though. I built a Thunderbird 1400 a few years ago in an InWin case that came with some "KingMax" 300W PSU. The motherboard totally baked. The clock generator chips actually had cracks in them. At first I thought it was just poor ventilation (ambient case temp stayed around 100F), but soon after I fixed the airflow and replaced the mobo the PSU completely died. I'm sure that was the problem all along.

I've had a couple cheap PSUs lose their cheap sleeve-bearing fans, too. Usually the fan starts making some horrible noise before it actually kills the PSU, though.

In one of my machines I have an 5-year-old EnerMax 365W PSU running a sad old XP 1600, and I have a 10K SCSI drive that refuses to spin up if I have two other 10K drives and a 7200RPM drive running. I'm 99% certain it's simply a PSU issue.

So, I'll agree with you somewhat that you really don't need an expensive PSU for a cheap system, but for an A64 or anything that you're going to have multiple hard drives in, I would certainly suggest something half-way decent.

For my personal system, I'll stick to Enermax Whisper PSUs. Of course Antec is always good if you want to save some cash on a case/PSU combo.

If you want something cheap, Fortron is at the top of my list for decent but cheap PSUs.

 

[halfadder]

I have killed many components on two of my PCs indirectly from using a cheap PSU.

A really bad PSU might work fine at first, but over time the voltages can sway and slowly burn out your components. Motherboard Monitor and other such apps can help you keep an eye on the various rail voltages, but the best solution is to just buy a well-tested PSU from a reputable brand.

 

[Shinare]

Thank you very much you guys for your valid input. You have talked me into getting the $36 Thermaltake 420W. Price is still a concern for me but from what I hear Tt is a good PSU. (any reason you all think I made a mistake with this one?).

Here are some answers to a couple questions posed to me:

System Specs?

MSI K8T Neo2-FIR (soon to be Neo2 Platinum cuz I wan the NF3-U)
a64 3000+ s939 winny 2.0GHz @222fsb
512MB Kingston HyperX PC4000 1:1
WD 200GB PATA 8MB
NEC 8x Dual Layer DVD +/- RW
Philips CD-RW
3 80mm fans on a Vantec Nexus fan controller
9600pro (soon gonna be a vanilla 6800)
Generic $7 350W Power supply

I forget the exact quote but "You been building for 15 years and you don?t know how important a PSU is??"
Yes. As another fellow stated (in a different way), a long time ago, you didn't choose what PSU you wanted to put in your machine, you put THE PSU in the machine. There were not 5000 different PSU options/manuf. to choose from. I remember the first time I saw a 200W PSU and thought to myself, "Damn, like that?s ever gonna be needed!" A 150W was par for the course, and was adequate. It wasn?t until a few years ago I even noticed that there were so many PSU's to choose from, and only right now am I asking the question does it matter.

I will take some educated opinions on the matter that involve more experience in the power area than I have (I will happily admit that) and get the better PSU. I do not have the test setup to check the oscilloscope to make sure the PSU is running correctly (however I do have a multimeter that I have used to make sure the voltages are correct before plugging anything into the PSU). One thing I didn?t understand, and was never explained to me until this thread was that 400W does not mean the same thing across different PSU manufacturers. It only seemed logical before now to think that was the same as saying a car engine has 100bhp can be directly compared to another different manufacturer's engine that has 100bhp.

Any other opinions on the matter?

 

[Cashmoney995]

See the solution is to use two powersupplies....two cheap one's at twenty bucks a pop should provide more than enough stable power for everything you got. I've used the 20$ Raidmax powersupplies which are 350 watts with great results, quiet, an don the test bed stable voltages.

 

[Sonic587]

Originally posted by: Shinare
Thank you very much you guys for your valid input. You have talked me into getting the $36 Thermaltake 420W. Price is still a concern for me but from what I hear Tt is a good PSU. (any reason you all think I made a mistake with this one?).


MSI K8T Neo2-FIR (soon to be Neo2 Platinum cuz I wan the NF3-U)
a64 3000+ s939 winny 2.0GHz @222fsb
512MB Kingston HyperX PC4000 1:1
WD 200GB PATA 8MB
NEC 8x Dual Layer DVD +/- RW
Philips CD-RW
3 80mm fans on a Vantec Nexus fan controller
9600pro (soon gonna be a vanilla 6800)
Generic $7 350W Power supply

I would generally not suggest TT, especially if you want to run a quiet system. They're still a decent budget buy, however.

http://www.newegg.com/app/View...=17-104-966&depa=0

Fortron is what I would recommend if you're tight on cash. Most other quality PSU manufacturer's prices start @$50 & up.

BTW, that's a pretty low power system. No wonder you're getting by on that generic. Even with the 6800NU, you won't be pulling much over 100W@load on the DC side.

 

[1sikbITCH]

I cannot believe out of all these posts nobody has pointed out the most important detail to be concerned with (outside of wattage). Unless I just missed it. Wattage isn't everything.

Nowadays more components use the +12v rail. 15 years ago, this was not the case. When you go to buy a PSU, you need to make sure there are enough amps on the +12v rail, and then you need to remember that they oftentimes lie (Edit- mislead is a better word) about it, so knock a couple amps off the listed rating. A 350w PSU with 18 or 20 amps on the +12v rail is better than a 400w with only 12 or 15 amps on the 12volt rail.

Read the chart in the middle of this page: http://www.bleedinedge.com/gui...ect/psu_select_04.html
As a matter of fact, the entire article seemed to give good information.

The rig in that chart will pull over 18 amps on the +12volt rail. I myself use an Antec TruPower 420, which can pump out I believe 22amps. When you buy a cheap PSU, it might only kick out 15amps, and then you've got a problem.

 

[Tostada]

This Fortron 300W PSU is $36 delivered. It's very quiet and has 18A on the 12V rail (newegg says 15A, but I just got one this week and it's 18A). It's better made than most $50 PSUs I've seen.

http://www.newegg.com/app/view...description=17-104-937

 

[Pandamonium]

Here's the way I see it (and this is a monetary explanation): if you get a top of the line system and skimp on the video card, you've created a bottleneck in the video subsystem. The same can be said for any other component. If it's the PSU, on the other hand, you probably DO NOT see any difference in raw performance.

Instead, the difference, if it manifests itself, comes in reliability and stability. Given the option of shelling out $50-80 for assurance in reliability and stability of a $1,000+ machine, most would accept.

The reason for the increased cost? "Cheaper" PSUs are put together with the cheapest components. Whether these components are quality is debatable- sometimes you luck out. More expensive PSUs are generally put together with more expensive components. I concede, however, that a considerable portion of their cost is for the branding.

Just realize that behind that inflated cost is also increased quality. It's similar to the difference between, say, Nike's sneakers and Target's sneakers.

 

[Corsairpro]

Fortron is one of the better "lesser known brands" behind PSU leaders like Antec and Enermax

 

[dnuggett]

Originally posted by: Cashmoney995
See the solution is to use two powersupplies....two cheap one's at twenty bucks a pop should provide more than enough stable power for everything you got. I've used the 20$ Raidmax powersupplies which are 350 watts with great results, quiet, an don the test bed stable voltages.

And how much time do you spend modding the case?

 

[silverpig]

EVERY cheap PSU I've bought has died on me. 4 in a row. I've fixed 3 others from friends who have had their computers "not work anymore" because of POS PSUs. On the other hand, every Antec supply I've every bought is still running like a champ.

 

[bendixG15]

And my wife insists on putting "High Test" gas in the car
cause it costs more and must be better.

I can't convince her that she is wasting money and harming the engine.
"You get what you pay for" is what she gives me.

Same for Power Supplies..if it costs more, it must be better.
The merchandising guys laugh all the way to the bank.....

 

[dnuggett]

Originally posted by: bendixG15
And my wife insists on putting "High Test" gas in the car
cause it costs more and must be better.

I can't convince her that she is wasting money and harming the engine.
"You get what you pay for" is what she gives me.

Same for Power Supplies..if it costs more, it must be better.
The merchandising guys laugh all the way to the bank.....

Lol... Im wondering what kind of car you are talking about what componenents make up your computer. Are they even worth mentioning?