# Need help with voltage terms



## Schotzy (Jan 4, 2009)

Could someone explain what these are; they are all listed under CPU voltage. ( I will list each setting and it's current voltage.) 

Load line calibration ( it's currently disabled)
CPU vcore- 1.2375 volts
CPU termination- 1.2 volts
CPU PLL-1.5 volts
CPU reference- .760 volts

Could someone explain what these are and tell me which one I need to increase?
I'm sorry but I'm pretty new at this and I can't find a guide to explain the voltage options. 

I have a Intel q9550 and a Gigabyte EP45-UD3P motherboard.


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## greenbrucelee (Apr 24, 2007)

The CPU core voltage (VCORE) is the power supply voltage supplied to the CPU (which is a digital circuit), GPU, or other device containing a processing core

CPU PLL Voltage - Selecting a higher PLL (phase lock-loop) voltage may help the installed CPU clock higher.

I think cpu termination is where you set it to cut off after the volts get too much

I have never changed the cpu pll and cpu termination, I have them on auto


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## Schotzy (Jan 4, 2009)

Thanks for the help for the help. I'm trying to overclock my q9550 and it won't boot past 3 ghz. What setting do I increase to up the voltage? Is there more than one?


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## greenbrucelee (Apr 24, 2007)

Yes there will be more than one setting, yours will probably be set on Auto at the moment.

On my motherboards BIOS I go down to the cpu voltage and press enter and it allows me to select from a list try this an if its the same as mine just select the next one up and see if it boots.


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## Schotzy (Jan 4, 2009)

Do I change the CPU vcore? What voltage is normal and what is dangerous for a quad cre CPU?


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## Aus_Karlos (Mar 10, 2007)

1.35v is the max for those Quad cores so you could try bumping it upto 1.3v and see if it boots.
CPU PLL i think (dont quote me) can go upto a max 1.8v. But many people can leave this on 1.5v
Leave the reference on default has it has more to do with data or address signals from the CPU to the CPUs on-board memory. If you have CPU GTL leave is on default as well. CPU ref and CPU GTL must be with a certain Ratio of each other. 

CPU termination is also known as FSB voltage, you dont need to tweak this much probably wont need to go to over 1.3v

@greenbrucelee

When overclocking its wise never to leave anything on AUTO. Ive done this mistake a few times. The BIOS will try and decide what is the best stable voltage for the current clock. Once i left my CPU on AUTO just to see what the BIOS does. I had set my Vcore to 1.3v, when i selected AUTO it decided that 1.5v is fine. When in fact it could of killed my CPU. If you don't want to change a particular voltage then set it to Normal.


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## greenbrucelee (Apr 24, 2007)

Aus_Karlos said:


> 1.35v is the max for those Quad cores so you could try bumping it upto 1.3v and see if it boots.
> CPU PLL i think (dont quote me) can go upto a max 1.8v. But many people can leave this on 1.5v
> Leave the reference on default has it has more to do with data or address signals from the CPU to the CPUs on-board memory. If you have CPU GTL leave is on default as well. CPU ref and CPU GTL must be with a certain Ratio of each other.
> 
> ...


Yes I realise this, I was just explaining to shotzy that his vcore is probably on auto meaning that it would be better if he changed it.


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## Aus_Karlos (Mar 10, 2007)

Forgot to mention, when getting to a high level of OC, +700mhz over its best to enable LLC (Load-Line Calibration). What this does is compensate for the volt-drop or vdroop when the CPU is under load. You will notice that if you set your voltage to say 1.3v and put your system under load it may drop to 1.27v. LLC tries to keep the voltage closer to 1.3v under load, this can really help with stability.


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