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Different BIOS and OS voltage

Tags:
  • Overclocking
  • i5-3570K
  • BIOS
  • different voltages
  • MSI Z77A-G43
Last response: in Overclocking
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September 27, 2013 5:47:52 AM

Hello! I try to overclock my i5 3570K on MSI Z77A-G43 board and I get quite different CPU voltage in OS from what I set in BIOS. No matter if I try turboboost or usual overclock with all power saving features disabled, I get the same results. As example when I set multiplier to 43 on every core in turbo mode and Vcore auto or +0.00V, I get 1.16-1.17V in BIOS and 1.25-1.26V in OS or even higher with turbo off. When I launch LinX AVX, Vcore drops to 1.216 and then to 1.192-1.20V during the test. I use Zalman 10X Performa cooler and get 79C with these settings. It seems very strange for me, I can't decrease voltage, there is only manual options with steps +0,02V, there is no LLC on this mobo too. Default BIOS settings don't change this situation. Any help would be appreciated.

More about : bios voltage

a c 164 K Overclocking
September 27, 2013 5:58:43 AM

Well those are well within limits. On Auto it is normal that it goes up from BIOS to OS since there is more load on the CPU.
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a b K Overclocking
September 27, 2013 6:19:40 AM

you could try enabling the power savings such as Intel Speedstep (EIST) as this will bring your voltage and cpu clock down when idling in windows. also, i believe you shouldn't disable Turbo if you want to use EIST as Turbo and EIST function together.

the fact that your voltage drops during a stress test shows me that there is some kind of LLC being used, if i remember correctly, for MSI Z77 motherboards, it should be called "Digital Compensation Level."

there is also another setting called "Vdroop Control" or something along these lines and both digital compensation level and vdroop control should be used together to achieve the closest possible voltage that you are trying to get. it's settings are in percentages from 0-100% in increments of 12.5%. but, it doesn't seem like MSI has included a description of what having less or more percentage actually does in neither manual nor BIOS... seems like you'll have to test the settings yourself to get an understanding of what higher or lower percentage values will exactly do.

im not sure why MSI didn't explain these settings more clearly but, i can definitely see it becoming a frustration simulator especially if the settings seem to behave erratically. :( 
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September 27, 2013 6:44:09 AM

mr1hm said:
you could try enabling the power savings such as Intel Speedstep (EIST) as this will bring your voltage and cpu clock down when idling in windows. also, i believe you shouldn't disable Turbo if you want to use EIST as Turbo and EIST function together.

the fact that your voltage drops during a stress test shows me that there is some kind of LLC being used, if i remember correctly, for MSI Z77 motherboards, it should be called "Digital Compensation Level"

Maybe such LLC option can be found on higher models of MSI mobos but I can't see it on this one. I use EIST and C-state options to decrease this voltage, however IMO it not suppose to be that high, 'cause I've seen much lower default values on other same boards (not even talking about +0,02-0,06 Vcore steps).
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a b K Overclocking
September 27, 2013 6:46:47 AM

try using Vdroop Control, i edited my post earlier, you may have missed it :) 
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September 27, 2013 10:59:27 AM

mr1hm said:
try using Vdroop Control, i edited my post earlier, you may have missed it :) 

Sad but it seems like there's no vdroop control option on this mobo too.
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a b K Overclocking
September 27, 2013 12:29:23 PM

rever5e said:
mr1hm said:
try using Vdroop Control, i edited my post earlier, you may have missed it :) 

Sad but it seems like there's no vdroop control option on this mobo too.



EDIT: that's for the G45, jsut noticed you had G43, let me see what i can find :D 

EDIT 2: http://www.madshrimps.be/articles/article/1000344/MSI-Z... - just start from the 4th page ("Testing Methodology and Results") if it doesn't take you there automatically.

- the link shows the board is indeed lacking many voltage controls for the CPU in the BIOS, not to mention, the fact that it's completely missing voltage options from the CPU's IMC (VCCSA/System Agent Voltage).

if it were me, id probably result to using OC Genie II if im having a hard time stabilizing small overclocks like 4.2-4.3GHz . id probably make sure to test it first though and see if it helps in raising and lowering CPU Voltages correctly since your manual overclock right now for some odd reason drops CPU voltage when under load.

if OC Genie II correctly raises (while under load) and lowers (while idling) cpu voltage, i'd probably try an use the settings that OC Genie uses and try to optimize it a little further. simply put, i just don't think there is much you can do due to the lack of CPU voltage controls.

is this a new PC setup for you? if you didn't get the mobo/3570k recently, how long have you had it? if you want to still overclock, i would highly recommend you upgrade that motherboard as it'll cause nothing but headaches later.

- something along the lines of a Gigabyte Z77X-UD3H (you could look @ some motherboards that are slightly cheaper around the $125-$150 range as well), will most definitely allow you to overclock higher with lower CPU voltage as well as have CPU/IMC voltage controls.
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September 28, 2013 4:26:26 AM

Yes, this mobo is definitely not a best choise, however I'm not going to change it for some reasons, I use it nearly a year. I suppose that something like auto vdroop (I didn't find this option as I said) causes high idle voltage that decreases under load. Vcore gets lower variation with C-state on so I would keep it enabled. I think I just have to deal with this.
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