Overclocking problem: sudden voltage jump from 1.2v to 1.5v!

hey guys,

Today I was overclocking my i7 950 (D0 stepping), and I was at 3.6ghz with a voltage of 1.25v (vcore) in BIOS, and I ran prime blend test for about 10-15mins, without any issues, and my core temp stayed under 63-64C on the hottest core. Then i bumped my multiplier from 21(175mhz base clock) to 23 (also 175mhz base clock) in order to reach 4ghz, and disaster. It booted to windows and after 2-3min after I finally launched cpu-z it read a voltage of 1.5v! I shutdown my pc, and haven't yet turned it on. The system was in idle, I didnt even run prime95 yet, and temperatures read in the high 50's (core temp)!

How is it possible that I had 1.25v in BIOS and then suddenly have 1.5v in windows, isnt the system supposed to crash if it has not enough voltage, instead of just overvolt? The core voltage was manually set in BIOS, while the others, except vtt were and ram, were set on auto.

My system specs:

i7-950 (D0)
evga x58 3sli
6gb 1600mhz
750watt corsair

120mm rad
danger den water block
swiftech pump

Could my CPU be damaged?
What should i do next?

Thank you in advance
11 answers Last reply Best Answer
More about overclocking problem sudden voltage jump
  1. You could probably go into the BIOS and back down the voltage before you hurt the CPU, but just to be safe, reset the BIOS back to factory settings. (Remove/reinstall the battery with the power cord removed, if you can't find the reset jumper)

    Then when you turn the computer back on, it should be factory speed and voltage.

    Then go back and overclock with the understanding that your motherboard will automatically increase voltage as you increase speed. In order to avoid your vcore going too high, you must lock the voltage down and set it manually, or use a negative offset so that the voltage is lower than the automatic voltage for a given speed.

    I prefer the offset method so that my voltage goes down at idle.
  2. I set the voltage in BIOS at 1.25v for the vcore, so shouldn't it stay at that, and if its not stable, shouldn't it crash rather than overvolt itself? Because I was stable with that voltage @ 3.6ghz, but when I went to 4ghz it automatically raised it to 1.5v. In BIOS it should still be set as 1.25v. Is that automatic overvolting normal?
  3. Also i have vdroop on, could that cause what I'm seeing?
  4. henydiah said:

    Others have gotten it past 4ghz, like in the review, what should I try?
  5. fil1p said:
    Also i have vdroop on, could that cause what I'm seeing?

    Yes, in part.
  6. So how should I approach this? should I reset my cmos and start over? Or should I attempt to turn on my pc and enter BIOS? Also what settings should I change for it not to go to 1.5v? Should I turn off vdroop? Or should I lower the voltage from 1.25v to something lower? I am not sure from where to start from, and I wouldn't like to have my cpu run at 1.5v again.
  7. Best answer
    I would turn off LLC. There is a risk in turning on a computer that, for one reason or another, spiked your vcore that high.

    It's a risk I would probably take for the sake of finding an incorrect setting and "knowing" why it spiked so high. I try to minimize risk when playing with other people's stuff though.

    So, I recommend reseting your BIOS to err on the side of safety. (and only enabling llc in small increments, after the rest of the OC is sorted out and you need to "fix" a vdroop situation to maintain stability..)
  8. Turn off LLC, go manual voltage?
  9. Best answer selected by fil1p.
  10. Thanks you guys for all your help, i have reset my cmos, and everything works so far. I am going to leave it at stock for now, later on in the future I might give it another try.
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