Vcore Question

[][v][AGIC]

I have what is in my sig powered with a ocz modstream 600watt psu. Question is in bios i have the voltage set to 1.4v but when i open up cpuz it says its only getting 1.32v. Which is correct? I my fsb is at 429 with a 7 multiplier for 3ghz and it boots to windows fine but fails after a wile in prime95. My temps are fine so i know i can up the voltage more but i am wondering if i am nearing where i shouldnt give it any more voltage (1.4v) or if i have some more room (1.32v).

[Thrax]

It's called VDROOP, where the vcore you set ends up being lower in practice as a result of power management not being perfectly accurate. You have more room, up to 1.5v on air.

[mas0n]

Does the BIOS report what it reads the voltage at? It is not at all unusual for the actual voltage to be lower than what VID is set in the BIOS. You won't know for certain unless you test with a multi-meter, but I would think that CPU-Z is correct with it's report of 1.32v. Either way if your temps are ok, you've got some room :)

[][v][AGIC]

Ok so i went up to 1.45v and it still locks up in prime. almost as soon as i start it. my memory is running at pc1100 at stock timings 5 5 5 15 at 2.3v. i tried using the sync mode so the memory just runs at stock pc800 and it still freezes in prime. So I'm thinking i hit a ceiling of 2.9ghz should i raise the vcore more to 1.5 or is likely to be all ill get out of the chip?

[Leonardo]

It's called VDROOPYou are technically incorrect. VDroop is the difference between vCore at CPU idle and vCore at CPU load. I would think that CPU-Z is correctDon't count on any utility being as accurate as the BIOS...if even that. The main readings to watch out for are 1) deltas - increases needed to obtain desired results 2) maximum safe vCore and vMemory. Your measurements will be close enough so that when get near the maximum, the +/- accuracy of your utility should be good enough for you to realize it's time to stop.

[TheLostSwede]

No Leo, you are wrong i'm afraid.

Vdroop = The difference between the set outlet pressure at a flow rate of zero and the outlet pressure at a given flow rate. Meens difference between BIOS setting and IC control.

http://wiki.extremeoverclocking.com/wiki/Technical_Terms

What you think of is some sort of Delta between Idle and load.

Magic, try this.

Lower the fsb to amore normal level, leave the multi, but set the memory divider so that you end up with a memory speed where you are now. Leave the voltages as they are. 1.45 volt is max you should use. Even auto on vcore might give lesses vdroop. Check the bios readings what the vcore is and compare it to what you have set it to. Try the above advice and let me know if this works any different.

[Leonardo]

No Leo, you are wrong i'm afraid.I nod in the direction of Thrax.

Thanks, Mac.

[mas0n]

Don't count on any utility being as accurate as the BIOS...if even that.

My past 4 motherboards in my main rig have all been had innaccurate voltage readouts in the BIOS, but the voltage reading in CPU-Z was always correct for me. I know that isn't always the case with all boards, but I have come to trust it more than any BIOS.

In the end, the only thing I really trust is my multimeter, but CPU-Z comes in a distant 2nd.

[Leonardo]

the only thing I really trust is my multimeterAnd I cannot argue with that. In your experience, what has been multimeter-measured difference from the BIOS readings? And also, what software has provided the best voltage readings in Windows?

[mas0n]

Usually the vCore measurment was ~.1v too high in the BIOS although I had one board which reported the vCore as much as .15v higher than I measured with the multimeter.
For some reason I have NEVER had a board report the correct voltages on my Antec Neo HE 550. The 12v always reads as ~11.7v and the 5v usually reads as 4.8v in BIOS. But with my multimeter (which has been tested to be accurate) I get ~12.08v and ~5.07v.

As far as software goes, i have not run the whole gamut of available utilities, primarily because CPU-Z has always worked well for me.

My current board, the ASUS Maximus Formula, reports vCore accurately although it still reports the incorrect 12v and 5v readouts. On a side note, the latest BIOS for this board drastically improves the vdroop that most C2Q seem to have. The delta of VID to actual voltage is never more than .02v now when before it was almost .1v under load.