What's the Problem With "Weak" PSUs? 3

[ErikRP]

I understand that I should always get the best (that I can afford) when it comes to, well, everything really, but PSUs especially.

I currently have a 350 watt PSU that is (as I recall) a pretty no-name brand. What I am concerned about is the 3.3V range(?) is set at 14 amps. In corresponding back and forth with my mobo manufacturer, they recommend 28 amps. What would an underpowered PSU do - what would it affect, specifically at 3.3V and what symptoms might I see? I was having some awful trouble with my system about a month ago when I first installed this new board in this new case but replacing the RAM seems to have made all the difference. (It's pretty sad when inserting a 128Mb-66 DIMM improves the performance over a 256Mb-133 DIMM, but bad RAM is bad RAM...) Anyway, I just want to make sure I'm not going to kill anything, so I want to know what I should watch out for.

I'd ask the mobo manufacturer (ECS), but it takes a few days or so turnaround in getting info from them, and this forum is much more helpful!

Thanks!

 

[franklin97355]

If your power supply can't provide the power needed to run things you will have problems. It may not kill your computer but it won't be reliable and things will go wrong.

 

[paparazi]

Voltage regulation is more precise, more reserve power when needed, higher quality components and better build quality plus the fact that the unit is much more likely to delliver what it says it will delliver, many cheap PSU's actually fail well before they reach there so called output figures.
All this combined means branded PSU's are infinately less likely to fail.
When you consider buying wholesale, cases can be purchased for as little as £15/$11 icluding PSU, it no wonder that build quality is poor and reliability even less so.
One last note* When they pop they usually take out other hardware, most commonly hard drives and even motherboards.

Martin
Please let members know if there advice has helped any.

 

[ErikRP]

Thanks for the input guys, but I was looking for something a little more specific. As it appears my 3.3V output is low, what would that affect - i.e. what is powered by the 3.3V output?

As I said, obviously you get what you pay for, and I admit I didn't pay a lot for my case, with PSU, but I want to know specifically what sort of problems I might encounter. I'm thinking that just because one range of voltage (in this case, 3.3) is low, it does not necessarily mean I have a low quality PSU that is likely to fail - is that correct?

 

[edfair]

BSOD. Boot failures. Probably would fail to drive address or data bus all the way and get addressing and data errors. Would probably show up as memory errors. Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[KimLeece]

3.3 volts normally powers your RAM and chipset. Also 2X AGP uses 3.3v - (4X uses 1.5v which is also derived via a voltage regulator from the 3.3v source)
Also - I know that 133DIMM is downward compatable with 100DIMM - but I didn't think it was truly compatable with 66DIMM - so if your motherboard actually has a bus speed of 66 then that would possibly explain why 133 doesn't work properly. (although I am not 100% sure - so you should check this last) But I think your mobo must be 66 as otherwise it couldn't use the 128-66DIMM at all!

kimleece

 

[ErikRP]

Thanks for the info!

This is the stats on my motherboard:

http://www.ecs.com.tw/products/k7sem_3x.htm

I don't think it's a 66 Mhz(?) bus speed, but I can't swear that it's not.

For what it's worth, yesterday I noted that the RAM operates at 3.3V which made me wonder if the problem was the power supply not giving enough juice to the RAM. I took my old 256Mb-PC133 stick back and got a new one and it seems to be working great now. So I'd say bad RAM, but I still think that the power supply should be replaced.

Finally! A month later - I have a computer!!!

 

[johnsnetwork]

ecs has a real bad problem with the voltage regulators on the motherboards. If they dont get a real clean signal the regulators die. the voltage regulators are right behind the cpu socket were all the round coils of wire are. The voltage regulators are inbetween the coils of wire. If they are getting hot. It means that they are being fed more voltage then they can regulate. Trust me the motherboard will be dead soon. when the board dies it has a nasty way of taking out most of the hardware connected to it. I learned the hard way i have the same board. It was replaced with a abit motherboard and a enlight powersupply.

 

[ErikRP]

Thanks Johnsnetwork for that voice of doom!

Is there a way to prevent such a death of my motherboard? You said that if it doesn't get "a real clean signal the regulators die". Does that mean a clean signal from the power supply or from the motherboard? If it's from the PSU, would a better PSU solve the problem?

I'm not doubting that there can be a problem with this mobo, but as I said the new RAM seemed to solve my problems. The question about the PSU was (I thought) mostly theoretical.

 

[Gloryhound]

when you have a low voltage you should notice that things supplied by the low voltage run a lot warmer or even hot which causes them to fail sooner or operate poorly. It is very possible that your "bad" ram was fragolaed by your low voltage, so keep an eye on your new ram and get a better PSU.

God Bless

 

[ErikRP]

I don't mean to question either Gloryhound or Johnsnetwork but Johnsnetwork is saying that my mobo's regulators can be fried by too MUCH voltage and Gloryhound is saying that my mobo will run hot if it has too LITTLE voltage.

Maybe I can answer the question myself and say that there is a relatively narrow band which the mobo likes, and too much or too little is not a good thing. Would that be right?

I'll keep an eye on things and see how everything is going. I am running MBProbe and it shows the 3.3V running at 3.22. The only other value that looks off is the -12V which shows as -11.07, which seems a bigger difference than the recommended 5% (by someone in these newsgroups). FWIW, the CPU temp is 44C and the mobo temp is 28C.

 

[ErikRP]

Well, I went out today at lunch and bought a new PSU - an Enermax EG365P-VE (350 Watts).

I had heard the Enermax was a good brand and the more I search here and the rest of the web the more sure I am that I will now have a quality unit that shouldn't be the source of any of my problems.

Thanks for everyone's advice!

 

[JohnCitron]

Erik,

It is important that the correct current is supplied to the motherboard to assure that everything is operating at its optimal level. Too much or too little current will cause the voltage regulators to work harder to produce the required voltages for the circuitry. This in turn causes them to dissipate more heat and burn out sooner than they should. As a hardware technician (I used to repair motherboards), I have seen burned circuit boards around voltage regulators and connectors due to this reason.

The manufacturer specified the 28A for the 3.3V because when they spec'd out the board they wanted to ensure that all of the components received enough power to operate properly. Too little will cause instability because the digital signals are not high enough, all the time, to switch other devices on and off. Too high a voltage or current will cause the voltage regulators to work harder as well as they attempt to keep the voltage at the right levels.

I hope this gives you a somewhat lengthy, but technical answer to your question.

John

 

[ErikRP]

Thanks John! That makes sense (or as much sense as anything makes on a Friday afternoon!). I'm going to put my new power supply in tonight. It's a little disappointing spending about $70 (CAD) for a good PSU and not really "seeing" anything new, but it will be some good insurance I'm sure, and well worth it in the long run!

 

[Gloryhound]

Yes a too high or too low voltage is bad. How ever 5% variation is typical of general electronic components. A high end unit should be able to keep things within a 1 - 2.5 % range of the target voltage. 5% should keep things close enough.

GBU!

 

[paparazi]

It is interesting your point about spending $70 and not really seeing anything new! I know this is why people stick with there cheapo Generic PSU's in the first place.
It's not like a graphics card or a new DVDrom, where there is something tangeable you can see and performance you can use.
BUT to anyone out there with a cheapo generic power supply in there system, being pushed to it's 300watt limit with your new TI 4600, 3 rom devices and 2 hard drives.
WHAT YOU HAVE IS A TICKING TIME BOMB!
it may never go off, but on the other hand if it does you'll be wishing you spent $70 on fitting something that didn't appear to be letting you "see anything new"
infact the best $70 you will ever spend on your machine. (in my opinion) Martin Replying helps further our knowledge, without comment leaves us wondering.

 

[edfair]

Mostly I agree but must add something.
All computers are ticking time bombs. Some tick faster than others. And a weak power supply is like lighting a fire under the bomb.
Since I'm not into bleeding edge stuff (don't like bleeding) I don't often hit the barrier. And so I continue with my <400mhz stuff with <250 watts. But if you are into high power processing, then spend the money for the PSU and memory. You'll be happier in the end. Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[ErikRP]

I'm not even in sight of the leading edge, however the generic PSU that I had was WELL below what was required for my mobo. I realize it's buyer beware, but when I buy a mobo and a case (with PSU) you'd think they'd warn me. It was an ATX form case which I would think should have a PSU with a certain degree of power.

In any case, the moral of the story is you get what you pay for.

Quick Postscript...

So far everything seems to be working really well inside the machine - no lockups or anything. I was surprised at first at how little air was blowing around at the back but I assume that's because it's acting as an intake rather than an exhaust.

 

[paparazi]

No! your Enermax definately blows out at the back, but it is either thermostaticly controlled (so the hotter it gets the faster it blows) or it has the little manual speed control button on the PSU rear that can be adjusted for speed.
Sorry if my earlier post sounded alarmist and I do understand that not everyone is running or wanting to run
&quot;cutting edge&quot; systems, sometimes I forget guys and gals.
Martin Replying helps further our knowledge, without comment leaves us wondering.

 

[ErikRP]

Thanks for the correction, Paparazi... It felt like it was blowing out but it was blowing so gently it was hard to be sure. The exhaust seemed pretty warm, so I'm surprised that it wasn't blowing faster but the temps are pretty cool <40C so I won't worry.