Load-Line Calibration enable/disable on OC?

[caaront]

Here is what the Gigabyte manual says about it:

Load-Line Calibration-Enabling this feature adjusts Vdroop, keeping the CPU voltage more constant under light and heavy CPU load.

Disabled sets the CPU voltage following Intel specifications.

Default- Disabled.


I was advised a while back to enable it, and I am at 4.2 GHz and stable with it enabled.

On one of the forums I visit in one of the threads several members told a guy to disable it because it could cause spikes in voltage and hurt his OC, but to me it sounds like the opposite is true.

Any advice?

Thanks, Aaron

 

[arterius2]

I have it enabled on mine @ 4.2ghz as well.

 

[caaront]

Here is a reply from one guy that gives me a better understanding, I have disabled it because like him I need my PC to last a while:

Vdroop (or rather, having LLC disabled) protects the CPU in the way described by this 2-page section of a 13-page article on AnandTech:

1. http://www.anandtech.com/show/2404/5
2. http://www.anandtech.com/show/2404/6

Enabling LLC disables vDroop, goes against Intel's specifications, and allows dangerous voltage spikes when overclocking like this. If it were a really small overclock, then I guess I wouldn't be worried. Or, if it were a 65nm CPU, then I wouldn't be worried either because Intel's 65nm CPUs can handle vDroop being disabled (or in other words, having LLC enabled).

But most overclockers/enthusiasts don't care because they don't want to keep their CPU longer than like 1 year anyway, so it doesn't bother them. But for people like me who can't afford a new CPU once every 1-3 years, I have an extremely strong preference for leaving LLC disabled!

This doesn't mean that the CPU would die after 1-3 years, but it just means that it's possible that its overclockability could either be reduced or eliminated - depending on the overclock and the voltage used.
__________________

 

[caaront]

After disabling Load-Line Calibration I had to raise the V Core and I raised the QPI/VTT to keep them within .5 of each other (I was directed to do this before so I always have) and even with very slightly higher voltage settings it is running 4C cooler during the 100% Load Testing, and it is stable.

Here are my basic OC settings now:

Load Line Calibration= Disabled

V Core= 1.300v

QPI/VTT= 1.300

DRAM Voltage= 1.660

IOH Core= 1.200

CPU PLL= 1.840

Clock Ratio= x20

CPU Freq= x36

BLCK Freq= 200

Turbo= Enabled (For 4.2 GHz)

Multi-threading= Disabled (I will conquer this one later, but I'm in no hurry).

C1E= Disabled

c3/c6/c7= Disabled

EIST= Enabled

Performance Enhance= Standard
System Memory Multiplier= 8.0

Memory Freq= 1600

QPI Link Speed= x36

Uncore Freq= x17

 

[caaront]

On some of the other forums there is quite a bit of discussion going on, some favoring enabling LLC, some favoring disabling it.

I googled LLC and read many many articles and here is where I'm at on the matter now:

Here's the deal put as simply as I can, both examples being OC'd.

1.LLC Enabled

With LLC enabled and the V Core set to 1.300v and at load there will be spikes and you will exceed the setting of 1.300v during these spikes.

However the lines on the tests will be mostly nice and flat so you will not see the spikes sending you over your set voltage, you would need to use an oscilliscope to see them.

So if you are at a very high OC with high Voltage settings you can exceed the safe voltages at load, and therefore the CPU may not last as long with LLC enabled.

2.LLC Disabled

With LLC disabled and the V Core set to 1.300v you will never exceed 1.300v at full load.

There are spikes at load whether LLC is enabled or disabled but with LLC disabled the V Droop lowers the Voltage just enough to ensure that the spike does not exceed 1.300v.


My opinion on the matter:

With LLC disabled I am at 4.2 GHz STABLE, I am running 4C cooler, and I will never exceed 1.300v on my V Core.

While wringing out FSX, I could not notice the slight V Droop at all, but I do notice the much cooler temps.

So for now and until I hear more convincing evidence to run my CPU at hotter temps with the same 4.2GHz I am going to leave LLC disabled.

NOTE:

FSX is worse than Crysis or anything else when it comes to FR's, and I am locked at 30 FPS in FSX at 4.2GHz with LLC enabled and my temps running 4C hotter, and I am playing it at locked at 30 FPS with LLC disabled and running 4C cooler.

So should I go for 30FPS hotter, or 30FPS cooler?

 

[caaront]

Look at this clear example of the voltage spiking from 1.23 to 1.245 at start of load and then to 1.25 at end of load with LLC enabled.

 

[4Ryan6]

It helps listing the CPU you're using regarding LLC, I always disabled LLC when overclocking my Q9550, it was already a master juggling act keeping 2 dual cores in sync with each other, you didn't need LLC throwing an additional variable into the mix, so for my input I always disabled it.

 

[caaront]

I7-920

 

[4Ryan6]

I7-920

Well I haven't had the pleasure and experience with the I7-920s overclocking Yet, regarding LLC, my experience is strictly regarding the Socket 775 Core 2 Quad Q9550.

 

[caaront]

Okay, and I do thank you for your input.

It's up to whatever someone wants out of their PC I guess.

I can run at 4.2GHz fine with LLC enabled at just 1.26875v, but at a temp of 77C.

Right now I am running at 4.2GHz with 1.300v, but at a temp of 72-73C at full load.

I am idling at a lower temp also.

I am only 2 steps up on my V Core, but I am running cooler 100% of the time that my PC is on.

I think that running cooler is better for the long term health of my PC than dropping down from 1.300v to 1.26875v.

I might be wrong though.

 

[RJR]

I think that running cooler is better for the long term health of my PC than dropping down from 1.300v to 1.26875v.

I might be wrong though.

No, you are 100% correct. If that's all the increase in voltage to be Prime stable you should disable LLC, you have no need for it.

My MB on the other hand has a .12v vdroop so It really gets up there if I disable LLC, but I don't have a scope to see what MY actual transient spikes look like so i'll just have to wait and see what ,if any, are the consequences of my actions. I've also run an Asus P5KC mb with a pencil mod (completely eliminating vdroop) for almost 4 years now with no side effects so I'll have to see. Your in good shape though, enjoy.

 

[caaront]

No, you are 100% correct. If that's all the increase in voltage to be Prime stable you should disable LLC, you have no need for it.

My MB on the other hand has a .12v vdroop so It really gets up there if I disable LLC, but I don't have a scope to see what MY actual transient spikes look like so i'll just have to wait and see what ,if any, are the consequences of my actions. I've also run an Asus P5KC mb with a pencil mod (completely eliminating vdroop) for almost 4 years now with no side effects so I'll have to see. Your in good shape though, enjoy.

Thank you, I feel much better about it, I thought it was a pretty small difference in voltage.

I forget that no two systems are alike though and someone else may have a pretty big spread.

 

[caaront]

Okay, I brought it down a notch to 1.29375v in the V Core, and 1.280v in the Qpi/VTT.
You will note that it is actually below that at idle and at full load, but it's stable. The highest temps were 72C-68C so I brought it down 1C in CPU 1-the hottest core.

Here are a few SS's: