Processor undervolted??

MedlockMedlock Miramar, Florida Member
edited June 2004 in Hardware
I've run my processor at stock speeds for a very long time, and under load, though it gave me no problems, seems to be undervolted. ASUS Probe reads 1.438, but the stock setting for a P4 Northwood is 1.525 isn't it? That is the current setting in BIOS, btw. I'm able to get up to 3.06 GHz at this setting. I tried upping the voltage slightly when I went up to 3.2GHz, but it didn't make much of a difference, and it was very unstable. (Folding@Home crashed, just the second console but not the first) So I put it back down at 3 GHz. I've been able to hit 3.2 GHz before, back in the winter/fall, but I've had to throttle it down a bit as temperatures have rised quite a bit and I'm not always around to keep an eye on things.

I'm thinking of bumping the voltage way up when my new heatsink arrives, but I'm not sure that will help a lot. Could my PSU be behind this, or is it this crappy mobo? I'm pretty sure it's the PSU. I was cheap and came with my casing. It's rated 520 watts, but you always get what you pay for right? My bios will let me set it up to 1.6v but I'm still not sure if I will get anywhere near that high if I actually put it up there.

See the picture I have attached...

Comments

  • csimoncsimon Acadiana Icrontian
    edited June 2004
    what psu is that?
  • muddocktormuddocktor
    edited June 2004
    Whoa, man! That 12v rail is really low and might be part of your instability problem.
  • MedlockMedlock Miramar, Florida Member
    edited June 2004
    I'm not even sure, but from what I can see through the side window, (about half the label) it says "AG 520W"

    I'll go see if I can find it on the 'net.
  • entropyentropy Yah-Der-Hey (Wisconsin)
    edited June 2004
    for whatever reason, mine tends to undervolt itself slightly. dual folding right now, cpuz tells me i waver between .504 and .520 ... never ever .525...

    \\EDIT: found where it is in MBM5 ... here's a pic of it right now
    mbm.jpg 100.6K
  • mmonninmmonnin Centreville, VA
    edited June 2004
    Is it this one?

    http://www.svc.com/ag52atxposup.html
  • MedlockMedlock Miramar, Florida Member
    edited June 2004
    Ha! Good work, mmonnin! Yep, that's it for sure. So is this box crap or is it something else behind the low voltage.

    entr0py, I don't know if asus probe will work with anything but asus boards. Give it a shot if you can I guess. I'm pretty sure it's quite normal for the voltage to be slightly less than normal when under load. I'd expect the voltages mbm5 is reading for you. But I get this crap.

    BTW, I'm not really sure what voltage it idles at. This computer is never idle.

    Edit:// Oooh. I didn't see your post, mudd. I really don't know anything about this stuff. lol I didn't know it was so low. I would have gotten a better PSU if I wasn't a relative n00b when I built this machine.
  • mmonninmmonnin Centreville, VA
    edited June 2004
    The 12V line is real low. Upping the voltage on the CPU will only strain the PSU more and more. A new PSU is your best bet.
  • MedlockMedlock Miramar, Florida Member
    edited June 2004
    Hmm... Maybe that's also behind the odd behavior of this damn cathode. It's set to sound activation, and when I play my music, (has to have bass, that's what sets it off, aside from particularly loud noises) the thing lights up REALLY DIM the first inch or so. The rest stays unlighted.

    Man that sucks. 2 LED fans and the cathode is all that's hooked up to the PSU, besides 1 cd-rw and 1 hdd, and the mobo of course... and the video card. I'll get rid of the cathode I guess. It's doing me no good now.

    ...What PSU do you guys recommend? I guess I really don't need that much wattage. I could prolly live with 350 with what I have now. Should I shoot for 420 or so?
  • mmonninmmonnin Centreville, VA
    edited June 2004
    350W of a quality PSU will be enough. I recommend Antec PSUS myself and I own 3 now and just bought a 4th.
  • Straight_ManStraight_Man Geeky, in my own way Naples, FL Icrontian
    edited June 2004
    I would do something else first.... Plug a $4.00 socket tester into your surge strip that computer is hooked up to. See if the ground error light comes on. Next, I would take the cord, and a voltage meter, see if when you run the red lead from VOM to the hot and the black lead to ground you get a flow of 110 volts or within a range of 100-120 Volts.

    If either have failed, and you plug in just a PSU, it and computer will get damaged as it tries to compensate for bad ground, unless you replace surge strip, know wall outlet is good, and you replace cord. The second test also validates your socket in wall if results are within the range I gave you, you will only have a flow that way at nominal if lines in house are good for ground, and if that test fails and you repeat in another socket in another room and get bad, either house has major grounding problems or cord is bad. At that point, would test wall sockets used for test with VOM directly, if they both test good, IE you get nominal power flow from hot to ground, then cord is bad.

    Checking outside of box zeroes problem to box or determines something cheaper than a PSU is best first buy from inimum expense, and with any of those things bad, new PSU will die fast and be erratic and you will get all sorts of grief. Cheap surge supplies and cords die more often than PSUs do. IF I am in teh field, I get customers to trust me by explaining why, and get many repeat calls from same folks and thier friends with this strategy of "make sure it is the box first."

    What really bothers me is this-- the negative 12 V is high (should be equal to or greater than the 12 V value by absolute value(no sign)), and that could be the 12 volt leg or a VERY bad ground in circuit, a resistive ground line or grounding route device. Corrosion, burned circuitry in surge strip, damaged cord, can all do this. PSU ends up feeding more wattage trying to force a ground flow through an inverted 12 V to get negative 12 V (that leg's inverted voltage is used to dampen voltage and amperage backflow, ie to draw down value on ground planes to null voltage) in motherboard, should be low wattage, and voltage equal to or greater than 12 on an absolute scale (take sign off to get absolute number)) and result is it is draining too much capacity through a inverison circuit, can't power computer right. Down here I get so many bad surge strips in use damaging or about to damage boxes, that I check that first, not saying this is necessarily so, but have learned to check each part of power flow from box to wall first. About 40% of the time I sell a surge strip only, 10% cord only, and 30% one each of those three-- the remaining time it turns out to be something else in computer or house circuit totally.
  • entropyentropy Yah-Der-Hey (Wisconsin)
    edited June 2004
    could having poor and/or outdated electrical systems cause this as well? cuz i know our christmas lights can take out half the house just cuz of the crappy wiring lol
  • mmonninmmonnin Centreville, VA
    edited June 2004
    He could always plug in another computer to that socket instead. He might even have more than one computer in that socket already.
  • edcentricedcentric near Milwaukee, Wisconsin Icrontian
    edited June 2004
    While you have your voltmeter out checking your supply pop open your case, grab a loose connector and check your PSU voltage.
    If you have 110V at the wall and 11.4 on the PSU then you really need a new PSU.
    One option if the line is bad is to invest in a UPS. Battery backup and voltage stability all in one. Not to mention lightling protection. I won't run a box without one.
  • CronoCrono
    edited June 2004
    So is this normal ? I dont really know anything about PSU readings.
  • MissilemanMissileman Orlando, Florida Icrontian
    edited June 2004
    All of you guys make some very good points. Bad ground, low PSU supply voltages, they all have an effect on the Vcore. One thing you all are overlooking is the obvious. All power going to the processor comes from the motherboard. All those mosfets that get hot aren't there for keeping things warm :) They do the dividing and regulating for CPU power. Now if input from the PSU is way off it makes it harder for them to do there job. They can't amplifiy the power available to them. One of the reasons all P4 motherboards can't handle Presotts is they can't produce low enough voltage with high enough current from the on board power regulators.

    The voltage drop while cpu loaded is normal. It is caused by the increased current demand from the CPU, but it should stay within 10% or less. This is due to the power regulator circuits usually being current controlled and not voltage controlled. They have to do it this way or all the boards would fry right away. I generally bump my Vcore up a notch in the bios to help with stability.

    After all this rambling I would say all the points made are great, but don't rule out one of the obvious possible fail points. Motherboards do have issues too.
  • mmonninmmonnin Centreville, VA
    edited June 2004
    Those voltages look great, the ones in the last pic.
  • muddocktormuddocktor
    edited June 2004
    Yeah, Crono, you have no voltage problems at all.

    This is what my IC7-G shows with my 2.4 at 3340 MHz, using an Antec TrueControl 550. I don't have the -12v and -5v reading shown because MBM is giving some ridiculously low figures for them, must not read them correctly.
  • CronoCrono
    edited June 2004
    Oh I see. I use a Q-tec 350w PSU. It's SILIENT. And yes I mean no one PEEP. It's temp controled and ever since I added two case fans it's fan barely has to blow air out. I love it. I might want to get a Zalman 400w though. It looks nice =)
  • MedlockMedlock Miramar, Florida Member
    edited June 2004
    Yeah, it's the ground. Only one ground socket in this room though. I'll see what I can do... Thanks for your help guys.
  • ShortyShorty Manchester, UK Icrontian
    edited June 2004
    Crono wrote:
    Oh I see. I use a Q-tec 350w PSU. It's SILIENT. And yes I mean no one PEEP. It's temp controled and ever since I added two case fans it's fan barely has to blow air out. I love it. I might want to get a Zalman 400w though. It looks nice =)
    Id recommend the Zalman, they are very very nice :) Solid on power too.

    However...

    http://www.short-media.com/review.php?r=128

    I still prefer what I have. A 480w Tagan. Silent but so powerful :)

    Considering it's powering an Athlon 64 3200+, two power hungry WD Raptors, two maxtor SATAs AND an additional WD JB hard drive, 9800xt, Audigy 2, DVD and CD writers .... it handles everything I can throw at it :D
  • MedlockMedlock Miramar, Florida Member
    edited June 2004
    Maybe not. Now that this machine is actually grounded I'm still getting the same low readings.


    ...dammit
  • entropyentropy Yah-Der-Hey (Wisconsin)
    edited June 2004
    TheGr81 ... those readings, in all likelihood, are false. I tested my 5v and 12v rails with a multimeter, and there were much different from what my mobo was reading. I got 5.08 and 12.08-12.1. If anyone knows, that's in the acceptable range, right? So, even though your board is reporting undervolting, it probably isn't actually happening, either in the rails or the processor. (Note: I have an Ultra 500W power supply ... Ultra, in case you don't know, is the Walmart of computer parts ;D I was pleasantly suprised to see that it was a decent PSU after all!)
  • muddocktormuddocktor
    edited June 2004
    TheGr81, if you don't already have one, go down to walmart or rat shack and buy a cheap ($10-20) digital multimeter for checking your voltages. Then you can check what is actually coming out from the psu while powered up by checking the 12v rail on the molex connectors and you can check all your voltages by sticking the probes into the back side of the ATX connector by the wires and actually see if Asus probe is reading correctly. If you do have 12v coming out of the psu and you are only showing 11.3-11.4v with Asus probe, then you might have something adding resistance somewhere in the ATX plug on the mobo, dropping the 12v rail voltage down.
  • MedlockMedlock Miramar, Florida Member
    edited June 2004
    I'll see what I can do... I think my dad's got one lying around somewhere.
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