i7-2600k voltage spike when adding 1 to the multiplier

[thermie]

Howdy. For a week 24/7, I've ran my i7-2600k CPU at 1.21v (LLC 5), at 4.0GHz, on a Gigabyte GA-Z68X-UD4.

I decided to up the multiplier by 1, letting each core run at 4.1GHz.

After rebooting, I was shocked to see the voltage go from 1.21v to 1.30v.  I did not change that parameter.
 
 
 


vCore is set manually to 1.20v and LLC is set to 5. Even on idle, I was not expecting to see such a gigantic jump.

I immediately reset the BIOS to 4.0GHz for now, back where it's been stable and delightful.

Am I unique in having this problem, adding 1 to the multiplier and then noticing a 0.09v increase in voltage? (I was expecting to see the same 1.21v and get BSODs when testing Prime95, but I did not expect to see 1.3v whatsoever.)

Thanks!

[thermie]

Well, chalk this up to another case of "had to manually re-set options for them to take".   

After manually re-setting every voltage indicator, the problem was corrected.

I am now testing 4.20GHz using LLC 5, and 1.225V (BIOS setting, which reads 1.245V in the "Current MIT Status" screen). Under the same parameters, in Windows, 1.24~1.26v is read in TouchBIOS (but has stabilized at 1.24V after 5 minutes in Prime95).

So far, temps are getting to 68C (core1/2/3/4/package readouts currently read 63/66/66/61/68 respectively). (Room temp is 29.4C (85F) right now.)

At 4.0GHz (1.21~1.22v, LLC5), with the same ambient room temp (29.4C), I usually saw 61/64/64/60/65C, so I am wondering if the extra ~3C (and 0.05v) for only +200MHz is really worth it... So I might need a better heatsink or at least fan (the Arctic Freezer Extreme rev 2's fan runs at about 1000RPM and is custom-fitted for the HSU).