What is Load Line Calibration and should I use it ?

[evo4ever86]

Hey all.

Currently ive got my 8700K @ 5GHZ 1.360v. Ive heard ppl mention stuff about LLC "improving" OCs or achieving higher OCs with LLC set to a certain level. Can someone please explain to me what LLC's actually is? Please explain it to me in simple terms as dont want to get confused lol. Also ive heard LLC effects vdroop which i dont understand either lol, can someone explain that to me too?

Please if ur knowledgeable about these particular two features can u explain it to me so I can easily get to grips of it lol.

Cheers guys!

[Arne Saknussemm]

Some things are complicated and have complicated explanations. Any simple explanation is going to leave stuff out.
With that caveat...here goes



Red line = ideal world
Orange line = real world
Blue line = real world with Vdroop...low LLC value

In the ideal world the voltage delivered to the CPU at idle is constant and when it has to work harder (load) it gets instant increase in voltage with no fluctuation and when the load is removed, it instantly returns to idle and the decrease in voltage is instant and without fluctuation. Red Line.

Of course this is not real. The voltage is never constant and any time there is a change in load, the components have to react, which takes time and often means they over or under react. Imagine you are arm wrestling with the objective to keep your hand perfectly upright. That's just like your CPU. If your opponent increases force or decreases force...you will have to react and you will see your hand moving because if he decreases force you will be pushing too hard and have to compensate. Orange line.

So, in the real world the voltage will under or overshoot as the CPU is asked to change it's load. These over or under shoots are what causes instability and the overshoots, in particular, can be damaging.

Knowing the CPU can overshoot to damging/unstable voltage (the red circles) Intel have come up with a protection mechanism...vdroop. This limits the voltage increase possible and therefore limits the possible overshoot. Blue line.

However, if your CPU needs the orange line for a certain OC you can see, that the protection mechanism of Vdroop (limiting the voltage) would cause the OC to fail. So, you are given control over Vdroop. By setting LLC levels you are adjusting the level of the safety mechanism. Essentially, moving the blue line up in steps...towards the orange line.

Hope that helps

[evo4ever86]

Some things are complicated and have complicated explanations. Any simple explanation is going to leave stuff out.
With that caveat...here goes



Red line = ideal world
Orange line = real world
Blue line = real world with LLC

In the ideal world the voltage delivered to the CPU at idle is constant and when it has to work harder (load) it gets instant increase in voltage with no fluctuation and when the load is removed, it instantly returns to idle and the decrease in voltage is instant and without fluctuation. Red Line.

Of course this is not real. The voltage is never constant and any time there is a change in load, the components have to react, which takes time and often means they over or under react. Imagine you are arm wrestling with the objective to keep your hand perfectly upright. That's just like your CPU. If your opponent increases force or decreases force...you will have to react and you will see your hand moving because if he decreases force you will be pushing too hard and have to compensate. Orange line.

So, in the real world the voltage will under or overshoot as the CPU is asked to change it's load. These over or under shoots are what causes instability and the overshoots, in particular, can be damaging.

Knowing the CPU can overshoot to damging/unstable voltage (the red circles) Intel have come up with a protection mechanism...vdroop. This limits the voltage increase possible and therefore limits the possible overshoot. Blue line.

However, if your CPU needs the orange line for a certain OC you can see, that the protection mechanism of Vdroop (limiting the voltage) would cause the OC to fail. So, you are given control over Vdroop. By setting LLC levels you are adjusting the level of the safety mechanism. Essentially, moving the blue line up in steps...towards the orange line.

Hope that helps

Okay thanks for the explanation it's helped. What I need is some exposure "playing" round with LLC. ATM my LLC is set to Auto, and my vcore is 1.360v. Would u apply any LLC on that? In the BIOS it ranges from 1-7. Lets pick out the most extreme levels in order to see the results more clearly.

If I set it to 1 what would happen to my vcore? or if I set it to 7 again what would happen to my vcore?

Thanks for the help its much appreciated!

[Arne Saknussemm]

Assuming that BIOS follows the general settings...LLC 1 would put you close to the Blue Line...i.e. your vcore at load will fall. LLC of 7 should limit the voltage droop to near zero...so your load voltage would be higher. Of course, at LLC 7 the overshoots you cant see will be high.

You have to understand that you can't see the overshoots in software...that's only possible with a sophisticated oscilloscope

[evo4ever86]

Assuming that BIOS follows the general settings...LLC 1 would put you close to the Blue Line...i.e. your vcore at load will fall. LLC of 7 should limit the voltage droop to near zero...so your load voltage would be higher. Of course, at LLC 7 the overshoots you cant see will be high.

You have to understand that you can't see the overshoots in software...that's only possible with a sophisticated oscilloscope

Ok so in term of overclocking would meeting half way at say LLC 3 or 4 be good? I'm just trying to figure out what level of LLC you'd choose when overclocking.

In my situation could I lower my vcore and set a level of LLC which would make it overshoot to 1.360v to keep in stable?

[Arne Saknussemm]

Ok so in term of overclocking would meeting half way at say LLC 3 or 4 be good?

Short answer...yes.

what level of LLC you'd choose when overclocking.

Personally, I allow Vdroop to do it's thing using minimal or no LLC...especially for 24/7 OCing. It is a good safety/longevity feature built into the CPU for a reason.

I would only ever try to negate Vdroop for short benchmark runs when pushing the limits of a CPU

[feedmeink]

I like shooting for middle ground on llc for every day use. Keep in mind the higher the LLC, the hotter the cpu. (From what I've seen)

[evo4ever86]

Ok cheers for the help guys! I think i pretty much know how it works now.

[Silent Scone@ROG]

Depends on the platform, but between 4 and 6 should be ample for most configurations. Understanding the requirement for VDROOP makes tackling LLC a little more digestible.

[ThrashZone]

Hi,
Does z270-370-390 even have a input voltage setting in bios ?
It would be kind of tough to measure llc effects without that wouldn't it.

On x99-x299 both have input voltages and show in hwinfo... and llc can be measured by max/ min vccin
Without vccin how would one measure the effects of llc