Hardware, software and power


I hate to ask this question, but is there any relationship between executing software and system power consumption.

We have a number of different motherboards that have burned out the onboard switching supply.

All systems have the same PCI cards, and the ambient temperatures are always <30C. The sytems seem to fail after about 12 mnonths, caps have dried up and the inductors/FETS seem to have been hot for a long while.

Sofwtare running on NT4 has run for much longer and has the hardware has not failed, but a software package running VB6 and a DOS window fails.

I really do not know how to approach this issue, other than to blame DOS for being thirsty and coverting all to 32 bit.

Am I nuts?

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

chances are that the problem could be related to the house hold power supply from the wall socket. You maybe having a high number of surges or brown outs which are causing problems with the P.S., invest in a small UPS or surge control unit for about £60 quid, monitor the differences, also are you buying cheap P.S. units invest in a good P.S.

Could just be shoddy power suplies being used. Cheap parts = more variation in power fluctuation (-12.00 vs -11.5) and if they using cheaper parts obviously wont last as long.
Good way to see if one power suply is generaly better then another, other then price brand etc is to actuly pick the thing up and  find which is heavier, because generaly the heavier one is using better components.
Kyle SchroederEndpoint EngineerCommented:
If said software is maxing out the CPU at 100% or close to it, then obviously more power is being run through the board (and caps) to the CPU...

Ultimate Tool Kit for Technology Solution Provider

Broken down into practical pointers and step-by-step instructions, the IT Service Excellence Tool Kit delivers expert advice for technology solution providers. Get your free copy now.

May be your MB's are ABIT MB's ???!!!
Agree with dogztar--a CPU being driven at full load will pull a lot more power than one which is mostly idle; this is especially true of modern fast processors, which draw truly amazing amounts of power at full load. (The top-speed processors from AMD and Intel draw more than 70W full load).
Agreed, dogstar.

Calculation of the appropriate power supply to use given your system depends on the exact specification of the system.

If you can give a complete list of all the hardware you are using, it would help to calculate the right PSU for your needs, or troubleshoot your existing hardwae.

If you could also list the specifications of the current power supplies you are using.

A common failure mode is for the output capacitors to dry up, and develop high internal resistance. On light/no load, no problem. But on a higher load, the unit tries to maitain the right average voltage at the output.
Due to the fact that the capacitor doesn't smooth properly, this results in HV spikes on the output. Usually these shut down the PSU.

You can tell if the capacitors are failing in a psu, if there is a large ripple (fluctuation in voltage).  You may also hear a high pitch audible whine on an overloaded switchmode powersupply indicating excessive load, or that faint burning smell.

To summarise, your PSU's capacitors are possibly blowing up because:

* They are exceeding their rated power

This might be caused by:

Power demand exceeds rated output
Power surges
A short short circuit
Fan failure in the PSU
The power lead in the back of the PSU gradually working loose.

A UPS would protect your power supply from:

Voltage surges and spikes - Times when the voltage on the line is greater than it should be
Voltage sags - Times when the voltage on the line is less than it should be
Total power failure - Times when a line goes down or a fuse blows somewhere on the grid or in the building
Frequency differences - Times when the power is oscillating at something other than 60 Hertz (USA) in GB a 240V 50Hz cycle is used.

This link: http://www.howstuffworks.com/question28.htm

Gives you more information on UPS's it may help you to decide if you need one and which type you prefer (or can afford!)

The mean time before failure varies from PSU to PSU but may be 50,000 hrs or 100,000hrs of continuos operation. About five to ten times the life you're getting out of them.

I hope this helps you to troubleshoot your problem.
billf041698Author Commented:
Thanks for the advise guys but maybe I wasn't specific enough, The power supply is on motherboard, and my specific query was 'Is there a relationship between executing software ie at 100% usage vs idle time, and the power consumed resulting in the slow cooking of the caps.
Kyle SchroederEndpoint EngineerCommented:
Hmm, must be some fancy motherboards...I've never seen a motherboard with an onboard powersupply...generally they're connected via an ATX header.

billf041698Author Commented:
..... the swicthing regulator, on the motherboard, you know the one with little 'chokes' and FETs ... there're working way too hard!

Oh, you're killing the motherboard regulators?  That's probably down to over-power.  Are you running older pentiums with ATX12V PSU's?  They're meant to be backwards compatable but... they're not in reality.

Try swapping them out with older pIII spec PSU's.
billf041698Author Commented:
The systems are brand new, that's whats so unusual, different motherboards, PSU (ATX) running on UPS, diiferent locations.

Thats why I'm asking whether running the CPU at 100% over a long period of time is to be considered inportant to the problem with high end PIII's and P4's.
It's a bit out of my league this, billf - given the timescale, but it definatley seems like an overheating/overcurrent issue.  The piii's should be run on standard ATX psu's - without that extra 4pin adaptor - hence ATX.  The P4's should be run on your P4 ATX12V type PSU.

As far as the motherboards go - are there any that are still alive running VB6?  If there are, it might be that those specific boards are running 4-phase instead of 3-phase power.  There might also be some relationship as to where the capacitors are placed on the board.

I can't say for sure, but the solution probably lies in three area's.  The first would be to the PSU's - try and use those that have the most steady current, say a specification of +/- 3% or less on all rails, and to make sure that they have optimal load.  The second would be only to use 4-phase+ combined (on the p4's) ?with custom upgrade heatsinks.  The third would combine this with extra case cooling - this might be in the form of faster exhaust case fans.  Another solution would be to lower ambiant temperature i.e. air conditioning.

Not exactly pinpointing anything here, I wonder if any other xperts have any ideas.  You can raise their attention by asking another question with a few points and direct them here.  jhance is the god of hardware here!

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
billf041698Author Commented:

I'm going to actually measure CPU & case temperatures under different software conditions. It seems Nobody will confirm or deny any relationship.

All the caps that dry out are right mext to the output inductors and FETs so i can't tell if the inductor is staturating and genetating the heat or the FETs. I did notice that the wire gauge is smaller on the output side with the same turns as the primary side with a higher gauge, seems reversed to me?

I'll checkout as you suggestions about the cabling.


It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.