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Lowering the PLL, why does it work?

post #1 of 7
Thread Starter 
So I was doing some preliminary stress-testing of my 980x (4.2GHz, 21x200, 1.35625v) and IBT errored out at the 21st test. I remembered reading something somewhere at one point about how lowering the CPU PLL has shown to improve stability in some cases.
So I went my jolly way and lowered it a notch (from 1.81v to 1.8v I believe), and so far it's at its 26th pass.

Of course, this doesn't mean very much quite yet, still have to do LinX 30 passes, and then after that 12 hours of Prime95 small ffts, and then I move to RAM OC'ing, but still, what does the PLL (phase-locked loop) do exactly?

Thanks!
post #2 of 7
I have mine at 1.8 also...Shouldn't you be able to lower your vCore alittle more? I'm at 4.2GHz with 1.31vCore, granted I know all chips are different but you're even water cooled!
post #3 of 7
That's one of the most difficult questions there is.
Stumbled on it myself quite a few times, and never got a real answer.

What I myself break it down to is:
A electrical loop circuit, where the in and outgoing values are checked if they match to what they should be.

But chances are my tiny brains misinterperted that completly.
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post #4 of 7
Thread Starter 
Quote:
Originally Posted by fliq View Post
I have mine at 1.8 also...Shouldn't you be able to lower your vCore alittle more? I'm at 4.2GHz with 1.31vCore, granted I know all chips are different but you're even water cooled!
I think my chip is just a singularly bad clocker What's your batch number? Got an F-batch and those are known to need a bit higher voltage than the B-batch 980x's. Tried it at 1.35v and that was unstable. Though keep in mind that was with the PLL at its stock setting, I'll try 1.35v with PLL at 1.8v.
Is your LLC at 100%? Mine is.

Quote:
Originally Posted by SandersAce View Post
That's one of the most difficult questions there is.
Stumbled on it myself quite a few times, and never got a real answer.

What I myself break it down to is:
A electrical loop circuit, where the in and outgoing values are checked if they match to what they should be.

But chances are my tiny brains misinterperted that completly.
Sounds pretty logical to me, I guess I'll just run with it

Thanks for your comments guys, +rep!
post #5 of 7
Every PPL voltage is the internal clock generator voltage. that is the definition of PLL and voltage. Anyways I think that the reason CPU PLL helps many people by lowering it, is that it lowers temperatures just improving stability.

I actually found though, that at high BLCK I need to increase CPU PLL>
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post #6 of 7
Yeah, I got a B batch. Yes, LLC is at 100% too.
post #7 of 7
Thread Starter 
Quote:
Originally Posted by Sin0822 View Post
Every PPL voltage is the internal clock generator voltage. that is the definition of PLL and voltage. Anyways I think that the reason CPU PLL helps many people by lowering it, is that it lowers temperatures just improving stability.

I actually found though, that at high BLCK I need to increase CPU PLL>
Alright thanks, will keep in mind.

Quote:
Originally Posted by fliq View Post
Yeah, I got a B batch. Yes, LLC is at 100% too.
Well there's your answer
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