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Bios freezing after undervolting an OC'd system

Hello there,

Recently I OC'd my i5 3570k to 3.8gHz (I know its not much but it is enough for me)
It runs stable at 62-67°C on heavy load (Planetside 2 ultra graphics) since 3 days but it skyrockets with prime95.

So I decided to decrease the temperature for the worst case scenario by undervolting the cpu. I read few forum threads about how much should i start with and most said 50-100mV.
First I took a look at the max vcore on Hardware monitor, which was about 1.225V

Proceeding to my Uefi-2003 Bios I lowered the Cpu core voltage from "Auto" (description said it had an offset by default: +0.005 - +0.61) to offset -0.1

Thought that if it was too much I could go back to bios and raise it again, I was mistaken.

After restarting the Pc, Windows couldn't boot up and it freezes at the "Press F2 or Del to enter bios" window. Now every time I press Del or F2 the screen becomes black and nothing happens.

After couple of restarts i managed to get into bios a few times, but it just freezes after 2 sec, not giving me enough time to change the voltage. I could see that the Cpu temp was 42°C and the vcore was 0.85V

So could a Cmos reset fix the issue? Or could I've done some serious damage to the Cpu?
Any suggestions?

-thanks in advance, and sorry for my bad english ^^

Oh and my mobo is P8z77 -m
3 answers Last reply Best Answer
More about bios freezing undervolting system
  1. You definitely want to reset CMOS. Your motherboard manual will have a detailed exaplanation for how to do it.
  2. Best answer
    If your motherboard doesn't have a clear CMOS button on it, just remove the battery for a minute then put it back in and that will reset the CMOS.
  3. benjii said:
    If your motherboard doesn't have a clear CMOS button on it, just remove the battery for a minute then put it back in and that will reset the CMOS.


    Ok thanks guys, I hope it fixes the problem.
    I'll let you know when i get back home, I'm currently in a Internet cafe searching for solutions ;)
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