LLC In Simple Terms ?

paulselhi

paulselhi

paulselhi

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I have searched and searched but cannot find a simple straightforward explantion of this

Basically i need to know what are the benefits/ non benefits of usng it
Is it better for the CPU or possibley harmfull
Does enabling LLC allow for lower cpu volatges or do we need higher voltages

Any explanations in terms that a muppet like me can understand would be welcome
 
Heated topic this one.

When the cpu is under heavy load it draws more current. This means the voltage applied to it falls. Overclockers don't like this, as below a certain voltage it tends to become unstable.

This can be dealt with by increasing the applied voltage, so when it droops down it's still high enough for stability. The problem is a high idle voltage, which is bad for the processor.

Or you can jerk the supply voltage up and down with changes in load. This gives a low idle and a low load voltage, but increases the magnitude of the overshoot that occurs whenever changing voltage. The voltage reaches higher and lower values, briefly, than it would do with a normal voltage supply.

So you can choose between high idle voltage, or unknown magnitude brief spikes in voltage when changing. Neither is good. We don't really know which is more dangerous. Intel choose the former. Years of overclockers saying that they don't like vdroop (and avoiding boards with high vdroop) resulted in the former.

I put my faith in intel's engineers, rather than in the thousands of overclockers who complained about vdroop. After all, it's ridiculous that the voltage would go down under load when this can make it unstable. Doesn't seem to matter much either way.

I wont use it.
 
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So the "former" intel method is with LLC off and would require a higher fixed cpu voltage in the BIOS? does this mean that cpu voltages would fluctaute but as a high cpu voltage is used the o/c can handle it and with LLC we use a lower cpu v but llc does the fluctuating to compensate?

My 4.2 Ghz o/c on a 930 seems to want LLC at level 2 ( gax58a-ud3r) im am using 21 x 200

Is a level 2 llc bad for the cpu/MB ? my cpu v is at 1.38125 and my cpu vtt is 1.375

should i try for stability with LLC off (standard) and raise my vcore ?

I can only seem to get a 4Ghz o/c stable at 1.4 Cpu in BIOS. CPU-Z shows this as 1.360 v

The difference between 4 and 4.2 ghz is slight for my rendering needs what i am concerned about is getting a stable o/c that will not damage the cpu or MB when rendering for 48 hours at 100 % cpu. ATM my my tmps on the 4.2 Ghz are 70 C when rendering and is using a lower cpu volatage so that looks better than the 4 ghz o/c
 
Voltages vary with load, llc is an attempt to reduce the variation which has the side effect of producing short duration large variations in voltage.

As I said, neither high idle voltages nor llc are good for the processor. We don't know which is worse. Hotter is definitely worse.

Ultimately it's your call though, if the chip degrades, buy a new one. If the motherboard blows, buy a new one. If you can't afford to replace either if it dies it might be worth considering a more conservative overclock.
 
I note in the gigabyte manual that it says the enabling LLC may cause longterm damage to the cpu/mb so i will not use it !!
This means i will stick with my 4.0 Ghz o/c LLC off as opposed to my stable 4.2 Ghz o/c LLC on

Now i, like other, folowed the gigabtye "official" overclock tutorial to get 4.0 ghz stable and also like others have found that need at least 1.4 CPU v in Bios it is not stable with anything less, shows as 1.360 v in cpu-z. It is however rock stable and i have rendered for 18 hours at 100 % cpu with temps at around 64 C

Can i relax now and enjoy the cpu as temps are fine at 65 c or less on 100 % load, or is this voltage just too much ?

If the voltage is too much are there ways to lower it and compensate in other areas (without uing LLC !)

Oh a bit of adivce to newbies like me, use a PS2 keyboard for testing as windows crashes wil not allow a USB keyboard to avoid the lenghty windows repair process
 
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There was a very good / thorough investigation into this by one of the review sites a while back (wish I could find it) that got the old oscilloscope out and looked at the problem properly from an engineering perspective. The conclusion found that eliminating vDroop (and the other one?) caused outrageously high spikes in the voltage (as described above) as the voltage tended to 'overshoot' when loading increased, to an unhealthy extent. Given that all of the case 'for' eliminating vDroop (and I too have soldered things to motherboards in the past to get around the 'evil' of droop) was based on short term anecdotal overclocking experience, I have to say the article was a real eye opener. The, quite frankly, smarter-than-us engineers at Intel really did know what they were doing when they devised this system, and I will never get in the way again!
 
Thing is those sites get very techy about it and just don't simply say whether it is best to have LLC ON or OFF i am going with OFF as per the warning in the MB manual
 
Might be this one you mean, reading it now. Probably not, turned out to be a theoretical article, no mention of o'scopes.

There's good reason why science and engineering are complicated. If you write them off as techy/boring then you simultaneously write off the chance of understanding. If you just want on/off answers, then in this case you want off since that's what intel recommend.
 
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Lets say for arguments sake i an get 4.2 Ghz stable and at 70- 75 c temps using 1.5 v cpu LLC off would this likely damage the cpu?

saying that i see on intel site that for the i7 930 VID Voltage Range 0.800V-1.375V i am running at 1.4 in bios 1.36 in cpu-z

Is there a way to lower the cpu v in bios and up something else to regain stability as it is only stable at 1.4 V bios
 
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