Is there a way to adjust idle voltage?

Archer0915

"The Expert"

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• Dec 8, 2011

• #1

Well I am doing a little undervolting on my 870 and setting it up as a VM server. It runs great at 100% load but will crash at idle because of the v reduction. At .720 actual it will crash and burn.

What I want to do is set the top end (That is easy) and the bottom end (not so easy). I know I can turn off all the neat power saving stuff and run with no power savings but that defeats the purpose.

 

EarthDog

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• Dec 8, 2011

• #2

Take off LLC...

 

Bobnova

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May 10, 2009

• Dec 8, 2011

• #3

Some boards have the option, but they're pretty rare.

 

EarthDog

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• Dec 8, 2011

• #4

Thats why I'm thinking that if he takes off LLC (as it seems its on due to vraise), he would have to raise the 'base' voltage to compensate.

 

Bobnova

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• Dec 8, 2011

• #5

That'd be a good start, yeah!
More vtt is worth trying too, just for completeness.

 

OP

Archer0915

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• Dec 8, 2011

• Thread Starter
• #6

Thanks for the replys and I will mess with it this evening.

 

OP

Archer0915

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• Dec 9, 2011

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• #7

LLC was off. I enabled it and all seems good.

100% 1.104 actual and idle 0.712 actual. I get error free crunching (boinc WCG) and crash free idle.

You guys made me look at the LLC and the fact that it was not enabled. I am going to run this for a few days and stress it in a few diffrent ways.

I will report and changes. As it stands this will make a great VM server as long as it runs stable.

 

EarthDog

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• Dec 9, 2011

• #8

Thats funny as the opposite should happen. When adjusting LLC, you are only adjusting the LOAD voltage...

 

OP

Archer0915

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• Dec 9, 2011

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• #9

EarthDog said:

Thats funny as the opposite should happen. When adjusting LLC, you are only adjusting the LOAD voltage...

Click to expand...

I have no idea. I mean I had it off in the first place and now that it is on it is idling fine. It could actually be that the change state was the issue and v was not such that a ramp up in clocks could be stabilized. The crashes occured when starting a program (CPUz and others, even browser) after idling. LLC may not affect the idle but it may affect the change state.

 

Bobnova

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• Dec 9, 2011

• #10

Last couple boards I've messed with LLC has raised the voltages across the board.

 

OP

Archer0915

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• Dec 9, 2011

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• #11

Well from my understanding LLC stabilizes voltages. Now when it does it I don't know but I think it would be on constantly in all states because there is a load or there would be no A and simply open V which means that a system would draw 0w on the CPU side of things. I believe what is happening is that without LLC the CPU demand is out pacing the normal capacity of the MB to meet the CPU needs as the clocks rapidly increase. With LLC enabled the CPU gets that hair extra boost where otherwise there would have been a hard droop @ multiplier increase.

 

EarthDog

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• Dec 9, 2011

• #12

It does it upon load. It minimizes the dip that is usually caused when putting a load on the processor. So again, it *should* only affect load voltages.

I guess its behavior is board dependent. Though the several I have had, its only on load.