Overclock.net banner
1 - 20 of 34 Posts

·
Premium Member
Joined
·
3,172 Posts
Discussion Starter · #1 ·
I've heard it 100 times "Don't use it with 45nm CPU's".
but...
I am having a little trouble getting stable over 420fsb, and if i could lower my volts my temps would be much better (my loads are 40C with low volts).

I am going to try a crossflash with a BIOS someone suggested first; if it doesn't work should I enable LLC?

::hope i don't start a flame war::
 

·
Registered
Joined
·
1,494 Posts
I have it enabled and on my e8400 and I haven't seen any problems. I think it becomes more of an issue when you are running close to the maximum voltage and you get a spike.
 

·
Premium Member
Joined
·
5,652 Posts
I have LLC enabled on my E8500. I think the major worry with LLC and 45nm chips is that they will volt to OVER specification. However, if you monitor your volts either in BIOS or other means, as long as they still stay under specs for max, I would think you are fine.
 
  • Rep+
Reactions: Aaroman

·
Registered
Joined
·
5,508 Posts
I agree with the above posters that LLC is fine, so long as you adhere to the voltage specifications of the 45nm chips. I wouldn't use LLC for anything past 1.3625v

I myself will never exceed 1.4v without LLC or 1.3625v with LLC.
 

·
Totally New to OCN
Joined
·
10,627 Posts
I am not sure I know what LLC is, but props for Optimus
 
  • Rep+
Reactions: Aaroman

·
Premium Member
Joined
·
5,652 Posts
Quote:

Originally Posted by StormX2 View Post
I am not sure I know what LLC is, but props for Optimus
LLC= Load Line Calibration.
 
  • Rep+
Reactions: Aaroman

·
Premium Member
Joined
·
3,172 Posts
Discussion Starter · #7 ·
Well lets try this RF 0802 bios first
 

·
Registered
Joined
·
5,508 Posts
Quote:

Originally Posted by StormX2 View Post
I am not sure I know what LLC is, but props for Optimus
not sure who Optimus is, but LLC is an abbreviation for a motherboard feature called Load Line Calibration, which fixes vdroop, an intel specification that is designed to lessen the voltage supplied to the processor such that if a voltage spike were to occur under load, it will not damage the processor.

I think alot would agree that 65nm processors can handle the erratic spikes that occur when Load Line Calibration is enabled, whereas 45nm processors, especially dual cores are more sensitive and vulnerable to these "spikes." Like I said before, I feel it's alright to use LLC so long as you're within the max specified voltage range for 45nm processors, 1.3625v.
 

·
Premium Member
Joined
·
17,407 Posts
vdroop is a safety measure to prevent voltage spikes when the CPU is put under load, or coming off of load. It is built into every board as specified by Intel. While this voltage spike doesn't seem to affect 65nm CPUs which have a higher voltage tolerance, they do affect the 45nm CPUs. I've seen people kill their 45nm CPUs when running max vcore and enabling loadline calibration. The voltage spikes are just too much for the 45nm core to take. It is important to point out that the voltage spikes are so quick, that they are not registered by any of the voltage monitoring programs. The spikes occur wen a CPU is going to a load state and when it is coming off from a load state:

(Note voffset is the difference between bios set vcore and what windows actually loads with)


Vdroop is the voltage drop when the CPU is under load. You can see this by opening CPU-Z at idle then noting the voltage drop when stressing the CPU by running Prime95.

Here is an article that explains voffset (vdrop), vdroop and the effects of Loadline calibration (LLC):

Anandtech: LLC

Here is what is happening with your voltage when the vdroop is eliminated, which illustrates the effects of voltage spikes:



Quote:
No Vdroop means the VRM circuit must work harder at maintaining a constant voltage

In this next case we eliminate Vdroop altogether and examine the chaos that ensues. As illustrated by our model, removing Vdroop does nothing to reduce the magnitude of the idle to full-load transient but does increase the settling time as the VRM must recover to a higher final regulation voltage. As in the case of no Voffset, it is possible to exceed the maximum allowable CPU voltage (VID). Clearly, removing Vdroop gains us nothing and only serves to create problems that are more serious.

So what happens when we remove both Voffset and Vdroop? The answer is simple - bad things. Although the difference between the maximum positive and negative peak overshoot are the same, severe violations to the CPU VID limit occur. If you're asking yourself what's the problem with this, consider the case of a CPU VID of 1.60000V - because the user feels this is the absolute maximum CPU voltage that they will allow. Just how high do you think CPU voltage will go after leaving a heavy load condition? We can't be sure without knowing more of the details, but we can certainly conclude that it will be well in excess of 1.6V. If you've ever run a benchmark only to have your system crash right as it finishes then you have experienced the consequences of this poor setup.

Finally, let's take one last real-world look at the consequences of removing Vdroop. ASUS' implementation of this feature, labeled as Load Line Calibration and included with their latest line of motherboards, is particularly worthy of our attention for a number of reasons. The first is that setting lower voltages with this option enabled actually results in a condition in which the CPU voltage under load is higher than the idle voltage. Imagine our confusion as we desperately struggle to understand why our system is Prime95 stable for days yet continues to crash under absolutely no load. What's more, in spite of the absence of droop and for reasons unknown, enabling this feature artificially raises our CPU's minimum stable core voltage at 4.0GHz from 1.28V to about 1.33V. As a result, our system uses more power under load than is otherwise necessary. Our efforts to reduce our processor's supply voltage backfired - instead of lowering the system's total power consumption we managed to affect a 20W increase.
 

·
Registered
Joined
·
468 Posts
The more I read about this, the more it seems to me that each manufacturers implementation varies in effectiveness. I see a lot if people with ASUS boards complaining, but not one person with a gigbyte board has seemed to have a problem... yet. I've been running LLC on my board without issue on my OC. Without it I have to run over 1.4v at idle to get my oc stable, which isn't a viable option for me.

I haven't noticed like anandtech that my idle voltage is higher. Even with LLC enabled, I see a very small drop in voltage on load.
 

·
Premium Member
Joined
·
17,407 Posts
Quote:


Originally Posted by javier
View Post

The more I read about this, the more it seems to me that each manufacturers implementation varies in effectiveness. I see a lot if people with ASUS boards complaining, but not one person with a gigbyte board has seemed to have a problem... yet. I've been running LLC on my board without issue on my OC. Without it I have to run over 1.4v at idle to get my oc stable, which isn't a viable option for me.

I haven't noticed like anandtech that my idle voltage is higher. Even with LLC enabled, I see a very small drop in voltage on load.

You wont see the voltage spike unless you have an osciliscope. People have significantly higher core temps with LLC enabled, which is another strange side effect.
 

·
Registered
Joined
·
468 Posts
Quote:


Originally Posted by ericeod
View Post

People have significantly higher core temps with LLC enabled, which is another strange side effect.

At the same voltage? I'd need to run significantly more voltage to get my chip stable at the same oc. I'm wondering what my temps will look like... I'm gonna go try it right now and report back in 30 minutes or so
 

·
Registered
Joined
·
5,508 Posts
Quote:


Originally Posted by ericeod
View Post

You wont see the voltage spike unless you have an osciliscope. People have significantly higher core temps with LLC enabled, which is another strange side effect.

I have a strange inclination to agree with javiar on this one. My vdroop is so bad on my board I'd have to set the value in bios upwards of 1.4v ++ just to get it to 1.31v on load that I need supplied to hit 4.2GHz.

All i'm doing is stabilizing my vcore, at the risk of some inadvertant, erratic spikes that will occur every so often.
 

·
Premium Member
Joined
·
17,407 Posts
Quote:


Originally Posted by jam3s
View Post

I have a strange inclination to agree with javiar on this one. My vdroop is so bad on my board I'd have to set the value in bios upwards of 1.4v ++ just to get it to 1.31v on load that I need supplied to hit 4.2GHz.

All i'm doing is stabilizing my vcore, at the risk of some inadvertant, erratic spikes that will occur every so often.

They occur each time the CPU goes to load and comes off from load. I'll admit, It is a highly debated argument. So for some, it isnt worth the risk, while for others it is. My only concern is that people are using it with their voltage already set to max. So the voltage spikes that occur have a much higher baseline from which they start from. If someone has LLC enabled at 1.30v vcore, and it spikes .15v, then your CPU is hitting 1.45v constantly when going to load or coming off from it. But if you are at 1.3625v with LLC, then you are constantly hitting 1.5125v...
 

·
Registered
Joined
·
317 Posts
Quote:


Originally Posted by javier
View Post

The more I read about this, the more it seems to me that each manufacturers implementation varies in effectiveness. I see a lot if people with ASUS boards complaining, but not one person with a gigbyte board has seemed to have a problem... yet. I've been running LLC on my board without issue on my OC. Without it I have to run over 1.4v at idle to get my oc stable, which isn't a viable option for me.

I haven't noticed like anandtech that my idle voltage is higher. Even with LLC enabled, I see a very small drop in voltage on load.

Yeah on my gigabyte board with LLC on, my load voltage is one notch lower then my idle voltage. I think that maybe ASUS does LLC a different way then Gigabyte.The ASUS board probably sets the voltage higher then idle while the Gigabyte board sets it one notch below idle.

So when the ASUS board senses the CPU go under load, it actually increases the voltage at in instance to be above the idle voltage which would cause the spike, as the gigabyte board just lowers the idle voltage by one notch so there isn't as much Vdroop so that the spike won't happen. That is what I think but I could be completely wrong.
 

·
Registered
Joined
·
5,508 Posts
Quote:


Originally Posted by ericeod
View Post

They occur each time the CPU goes to load and comes off from load. I'll admit, It is a highly debated argument. So for some, it isnt worth the risk, while for others it is. My only concern is that people are using it with their voltage already set to max. So the voltage spikes that occur have a much higher baseline from which they start from. If someone has LLC enabled at 1.30v vcore, and it spikes .15v, then your CPU is hitting 1.45v constantly when going to load or coming off from it. But if you are at 1.3625v with LLC, then you are constantly hitting 1.5125v...

The diagram in your other post shows ~.08v spike.

Therefore at 1.3625v, even with LLC enabled the most you'd likely hit would be 1.45v

So basically you have to ask yourself if erratic spikes at 1.45v would be considered "damaging" to the cpu.

I would also like to suggest that different boards have a different alrogithm or circuit designed to handle the specifications of vdroop, as javier mentioned. So I guess on some boards LLC would be worse to employ than others.

LLC is, for all intensive purposes nothing more than what the pencil mod is.

All it is doing is circumventing vdroop and stablizing vcore; and with that there are erratic spikes on/off cpu load.
 

·
Premium Member
Joined
·
17,407 Posts
Quote:


Originally Posted by jam3s
View Post

The diagram in your other post shows ~.08v spike.

Therefore at 1.3625v, even with LLC enabled the most you'd likely hit would be 1.45v

So basically you have to ask yourself if erratic spikes at 1.45v would be considered "damaging" to the cpu.

I would also like to suggest that different boards have a different alrogithm or circuit designed to handle the specifications of vdroop, as javier mentioned. So I guess on some boards LLC would be worse to employ than others.

LLC is, for all intensive purposes nothing more than what the pencil mod is.

All it is doing is circumventing vdroop and stablizing vcore; and with that there are erratic spikes on/off cpu load.

I should have mentioned I was using an arbitrary number since it isnt specified. I should have used a more conservative number though.

But I've seen 3 dead CPUs from LLC, so I wont be using it.
 

·
Registered
Joined
·
5,508 Posts
Quote:


Originally Posted by ericeod
View Post

I should have mentioned I was using an arbitrary number since it isnt specified. I should have used a more conservative number though.

But I've seen 3 dead CPUs from LLC, so I wont be using it.

I think we've all seen those dead cpu's.

And we've heard the reports from XS.

I'd like to think that so long as you're within the 0.85v-1.3625v range with LLC you'll be fine -- you probably wont see any chip degradation or just a down right 'dead cpu.'

It's possible that 1.3625v with LLC is pushing it.

However, just consider: what's worse, (for example) 1.425v without LLC or 1.3625v with LLC.

You take your pick. To me, they're both the evil parts of the spectrum.

I'd like to vouch that staying as close to the 1.3625v intel "max" is wiser than straying further away from this value. We have also heard this myth floating around that the real 24/7 max volts you should ever use is 1.45v.

Personally I will stick with intel's rated max and give a little room for some error +/- 10% ie. 1.4v for 24/7 use.
 

·
Registered
Joined
·
468 Posts
Jus an fyi-
I did some quick testing on my setup.
With LLC Enabled - Min load voltage in windows: 1.32v, Max voltage (at idle): 1.33v, Max temp: 56c
Without LLC enabled - Min load voltage in windows: 1.30v, Max voltage (at idle): 1.36v, Max temp: 54c

For me, this is a wash. The voltage on load is lower so the temps are a bit lower which is no surprise. I see no evidence of either producing different temps. They seem to be in line with each other...
 
1 - 20 of 34 Posts
Top