Energy efficient Sandy Bridge overclocking

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Manabu
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Energy efficient Sandy Bridge overclocking

Post by Manabu » Fri Jan 20, 2012 2:54 pm

I just got an Core i5 2500k on a Asus P8Z68-V, and oveclocked it to 4.5Ghz with a +0.075 vcore offset (could get more, but with too high temperature/noise and voltage).

The problem is that this overvolt also extends to the idle voltage, that is now needlessly over 1.000V. And I also can't lock it @1.6Ghz when I don't need the additional performance, but want silence and less power consumption.

I used to use k10stat on my Phenon, but I haven't found anything similar for Sandy Bridge. What can I do?

Also, this Asus board has lots of options that affect power usage, especially the VRM tunning and EPU. Most of what is written on the VRM tunning is directed at extreme overclocks. I assume that setting everything to the lowest/regular settings is the best power-wise, right? And I couldn't find any detailed explanation on what EPU do, and the difference between the light, medium and extreme power saving settings. So, I set it on auto. I also disabled every on-board controller that I don't use ATM (j-micron e-sata, bluetooth, etc), and I hope that it cuts the power they use.

cmthomson
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Re: Energy efficient Sandy Bridge overclocking

Post by cmthomson » Sun Jan 22, 2012 6:10 pm

If you dial back your overclock to 42x or so, you shouldn't need any extra voltage at all.
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Manabu
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Re: Energy efficient Sandy Bridge overclocking

Post by Manabu » Sun Jan 22, 2012 6:54 pm

Yes, but that means 7% less performance when I need, still more voltage than needed at idle (I probably can undervolt it further, but I haven't tested), and I would still want to lock it at an lower performance when I don't need the full speed. W/o reboots.

But I may end up doing it if no better solution exists...

darkb
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Re: Energy efficient Sandy Bridge overclocking

Post by darkb » Mon Jan 23, 2012 12:27 am

If you stiill have speedstep etc enabled you can set the maximum processor speed in % in the advanced power management area in vista and win7. So you can setup different power profiles with different Max speeds.

Vicotnik
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Re: Energy efficient Sandy Bridge overclocking

Post by Vicotnik » Mon Jan 23, 2012 4:49 am

In order for the overclocking to be energy efficient the system needs to do the same work while consuming less energy. Otherwise it's not efficient but just regular overclocking, right? ;)
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HFat
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Re: Energy efficient Sandy Bridge overclocking

Post by HFat » Mon Jan 23, 2012 5:19 am

The issue seems straightforward enough: is there something like RMClock for desktop Sandy Bridges on Asus? Not that I know of...

Manabu
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Re: Energy efficient Sandy Bridge overclocking

Post by Manabu » Thu Jan 26, 2012 11:04 am

I found this thread: http://www.xtremesystems.org/forums/sho ... ntel-board

And inside it, a reference to the RealTemp software: http://www.techpowerup.com/downloads/20 ... 03.70.html

With Real Temp I can easily disable the turbo, dropping down to 3.3Ghz, and this also brings the voltage down a little, but not the optimal amount. So, still not where I want (overvolt if 4.5Ghz, really undervolt if less).

I'm not sure if messing around with those registers on the first link one can make an RMClock/k10stat for sandybridge.

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