Formulating how much VCore is needed

Soldato
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I ran a stress test with CPU Z and noted what the vCore was at max load, then i noted idle VCore on a 4690K.

Vcore load 1.130v

Vcore Idle 0.708v.

this tells me a increase of 0.42 v is needed for a 3.1Ghz increase from 800mhz idle speed max speed 3.9ghz Turbo , all settings in BIOS on Auto.

Question.

Is it realistic to calculate what Vcore is needed per 1 ghz or even per 200mhz?

because with the above data , i worked it out that a .10v increase in needed per 800mhz increase in clock, all based on how the system automatically regulates Vcore when stressed/idle.
 
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Soldato
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I would say no, simply because its rarely linear relationship. As you go up the scale, higher clock speeds will take a higher proportion of voltage to stabilize typically.

Also one data point is not really enough, more so with auto settings. As an example, with Auto on, getting to 3.8 Ghz may only use 1.110v, while getting to 4.0 ghz may use 1.150v, you would really need to chart more frequencies to get a better idea of the pattern IMO.
 
Soldato
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I see. I understand, thanks.

Quite new to overclocking , and was just trying to find the lowest stable Vcore possible with any given clock increase.
 
Caporegime
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I've had an i5 3570K which needed 1.45V to get to 4.4GHz, and I've had an i7 2700K which needed 1.38V to get to 5GHz.

It depends entirely on the individual chip as well.
 
Man of Honour
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It needs whatever it needs, simple as that. You won't get two cpu's exactly the same either. There is no short cut way to overclock, you just have to keep trying until it's stable although it's much simpler these days than in the socket 775 days. Overclocking back then could take several days and even then what you thought was stable turned out not to be and you had to tweak some more. People can give a list of settings but nine times out of ten the settings will need tweaking for each different setup.
 
Caporegime
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Not linear and every chip is different.

One chip could need less voltage at idle than enough yet need more voltage at the same overclocked speed.

I basically work backwards with my overclocks. Set max safe voltage for my cpu, dial in the overclock i want, drop voltage down step by step and test until it falls over. Put voltage back up one step. Job done.
 
Soldato
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Not linear and every chip is different.

One chip could need less voltage at idle than enough yet need more voltage at the same overclocked speed.

I basically work backwards with my overclocks. Set max safe voltage for my cpu, dial in the overclock i want, drop voltage down step by step and test until it falls over. Put voltage back up one step. Job done.

This is what I'm currently doing. at.1.2v @ 4.4ghz. it just crashed at 1.8v
 
Caporegime
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1.8? 1.8?! :eek:

No, nonono... You don't want to go much over 1.35V.

1.8 is enough to make it pop like popcorn. You're lucky it only crashed. :p
 
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