Nehalem (i7, i5) – possible to under-volt in software?

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smilingcrow
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Nehalem (i7, i5) – possible to under-volt in software?

Post by smilingcrow » Thu Jul 30, 2009 5:09 am

Nehalem seemingly has a much more sophisticated way of handling power management with Lynnfield having a more advanced version than Bloomfield. Is it possible to change any parameters of the Power Control Unit which handles power management and Turbo Boost from within Windows?

RMClock doesn’t mention Nehalem support and neither does CrystalCPUID so I’m wondering if this is the end of the road for software control. Windows 7 x64 support might be another stumbling block as well.

The other possibility is that motherboard vendors produce utilities that will allow control of voltage. E.g. Gigabyte produces EasyTune which allows under-volting. Do Core i7 boards support under-volting with proprietary software?

Does Phenom II work with RMClock or CrystalCPUID? Or is there an AMD utility that allows undervolting? My first thought is that AMD’s software will only work with their own chipsets.
It could be good news for AMD if Intel disables external control of the Power Control Unit as tweakers may favour their platform over Intel.
I like the sound of Intel’s Power Control Unit and with a 32nm CPU it should allow some very efficient performance. It’s nice to have the option to tweak though. :D

loimlo
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Post by loimlo » Fri Jul 31, 2009 7:27 am

Intel i7's Speedstep works flawlessly within windows. So no need to bother with mainboard maker's proprietary software.

On AMD side, you can use K10stat software to control vcore based on CPU loading other than normal AMD CnQ setting. Btw, AMD CnQ or K10stat is transparent to choices of chipset vendors on motherboards.

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Post by smilingcrow » Fri Jul 31, 2009 10:33 am

loimlo wrote:Intel i7's Speedstep works flawlessly within windows.
I’d assumed that Speedstep actually works but was wondering how much control if any it is possible to exert on its parameters from within Windows.
loimlo wrote:So no need to bother with mainboard maker's proprietary software.
That depends on what you want to achieve. For the LGA775 platform RMClock and similar only allow you to change voltages within the VID range for a particular CPU. That’s very useful but also useless if you want to aim for a decent over-volt or under-volt whereas utilities like Gigabyte’s Easy Tune allow a very full range of control.
loimlo wrote:On AMD side, you can use K10stat software to control vcore based on CPU loading other than normal AMD CnQ setting.
Is it limited to the ‘natural range’ of voltage settings that apply to a particular CPU or can you go beyond that?
I thought there was an AMD utility that gives a lot of control and that the parameters that are accessible depend on the chipset used!

Does anyone have first hand experience in these areas?

loimlo
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Post by loimlo » Fri Jul 31, 2009 6:45 pm

Sorry, no 3rd party software for i7 for the time being. And Speedstep works with modest OC anyway.

K10stat can control CPU Vcore, NorthBridge's voltage beyond CnQ settings. As for AMD's proprietary software, AMD OverDrive is capable of changing tons of voltages manually, but I don't like this method. Well, I guess a picture is worth more than thousands of words, so I present my oced X2 245 result to you nonetheless.

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Post by thejamppa » Sat Aug 01, 2009 12:15 am

.. and peoples complain when there is no Black Edition's in Athlon II-line up... Honestly do you need Black Editions if you can overclock mainstream CPU's well?

Anyway its nice to see someone else using Athlon II.
If seeing is believing, how can blind person believe in anything?
Maturity is just not experience in life but also ability to make compromises.

darkb
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Post by darkb » Tue Aug 04, 2009 4:38 am

As far as intel speedstep control goes, you can set the max and minimum processor frequency in the power profiles in vista and windows 7, and limit what frequency / voltage settings it will use. I can step my i7 down through each whole multiplier by changing the max frequency setting while it's under load, and every step down lowers the voltage as well.. 21x down to 12x with my i7 920. (1.25v down to 1.05v iirc)

This would be very handy for htpc's, you can limit the max frequency to just over what's needed for smooth playback while still having it slow down further when not under load.

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Post by smilingcrow » Thu Aug 06, 2009 6:29 am

darkb wrote:As far as intel speedstep control goes, you can set the max and minimum processor frequency in the power profiles in vista and windows 7, and limit what frequency / voltage settings it will use. I can step my i7 down through each whole multiplier by changing the max frequency setting while it's under load, and every step down lowers the voltage as well.. 21x down to 12x with my i7 920. (1.25v down to 1.05v iirc).
Thanks for that, I didn’t realise that Vista/Win7 supported setting the multiplier range. I assume it will use the preset VID for each multiplier?
darkb wrote:This would be very handy for htpc's, you can limit the max frequency to just over what's needed for smooth playback while still having it slow down further when not under load.
Would that actually make any difference? I say that because Speedstep automatically raises and lowers the Speed/VCore depending on load; that’s what it does!

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