vcore dropping under load

[hawtrawkr]

how much of a drop in vcore is too much?

im running a p4 2.8c with a 1.67 vcore idle and itll drop to as low as 1.59 under a load is this to much of a drop?

[Gautam]

That amount of a drop in core voltage is on the precarious side, and may compromise stability. Usually a drop of about .05v is the highest you'd want to have. What power supply do you have?

[hawtrawkr]

just says iso switching power supply it came with tower. figured it was some generic 450 watt psu that should probably be replaced at some time but i dumped pretty much all the money i had at the time in new parts so i didnt upgrade yet. now however im starting to think that the stability is limiting my oc because ill run prime fine at a lower vcore than what im using now and eventualy itll just dip so low and thats when i notice prime crash out.

[mata2974]

as stated above no need to worry

[squads]

Originally posted by hawtrawkr
just says iso switching power supply it came with tower. figured it was some generic 450 watt psu that should probably be replaced at some time but i dumped pretty much all the money i had at the time in new parts so i didnt upgrade yet. now however im starting to think that the stability is limiting my oc because ill run prime fine at a lower vcore than what im using now and eventualy itll just dip so low and thats when i notice prime crash out.


thats definitely your psu. it cant supply the voltage you need for your o/c

[hawtrawkr]

think im going to order a antec true power 550 when i get a chance and see how that goes

i got quite a few things running off this one psu anyone know a url that has a list of what diffrent components use on avg?

[Oklahoma Wolf]

ISO isn't generic - it's a subsidiary of Channel Well Tech, who is the OEM manufacturer for all current Antec units. However, I'm not impressed with their model numbering scheme, which doesn't tell you what the true power rating is. If it's the ISO-450 you have, then it is a 350w PSU (www.cwt.com.tw has all the specs - their highest watt model, the ISO-500, is only a 420w similar to mine).

I would surmise a Truepower 550 (or CWT-550AD) will be a big step up, but I'm not totally sure it's the cause of your problem, as the mainboard's regulator circuitry would likely have more impact. That said, you do have a lot or stress on the 12v and I would go for the upgrade myself as CWT's lower watt offerings (below about 380w or so) seem a bit weak to me, and the ISO series seems to be bottom of the line.

[larva]

To be honest this degree of Vcore fluctuation is normal. Only when the sampling frequency of the monitoring is really low and/or the monitoring circuit is heavily dampened will the Vcore sit completely stable. Up to .08V fluctuation is normal even with the Abit's excellent 4 phase power supply's exemplelary regulation.

Most people don't really care what is actually happening in the computer, as long as the MBM readout is picture perfect. What we see as the hardware monitoring information is generally of low accuracy and should not ever in itself be taken all too seriously. It's not that it's totally useless, but on the other hand it is best not to obsess about the fine details of what it reports.

What you need to do here is put a voltmeter on the 12V line and check the idle vs loaded values. If the 12V is dropping appreciably a stronger power supply may reduce the Vcore fluctuation. But in most cases it's not going to dissapear entirely, .04-.08V is just normal if the monitoring is fast enough to show it.

[hawtrawkr]

ill check my 12v with a multimeter and see what it does idle/load.

[hawtrawkr]

k just checked 12v side with my meter and at idle it sat steady at 11.96 when i fired up 2 primes it droped to 10.84!! :eek: then it bounced up around 10.9 to 11.4 :( . i have to admit i was pretty shocked when i saw the 12v line drop so low

[Oklahoma Wolf]

Originally posted by hawtrawkr
k just checked 12v side with my meter and at idle it sat steady at 11.96 when i fired up 2 primes it droped to 10.84!! :eek: then it bounced up around 10.9 to 11.4 :( . i have to admit i was pretty shocked when i saw the 12v line drop so low

Wow - that's pretty conclusive the PSU can't handle that o/c'd P4 too well... a Truepower 430 or better, or Fortron 530 would fix that issue.

[BrianS]

yes that is rough, and could damage some hardware. i have an abit 3-phase mobo with a 510w pcp&c PS and MBM5 reports 1.65v-1.73v vcore when i have it set at 1.7v. even the best hardware can have power fluctuations and mbm5 voltages are not to obsess over