i7 2600k Overclocking with EIST/SpeedStep

E

ExGreyFox

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Sep 18, 2012
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Hello guys,

I have been able to successfully overclock my 2600k using Theocnoob's overclocking guide. I reached 4.5GHz at Vcore 1.31. Right now I am using the manual method of adjusting the Vcore so my CPU frequency is constantly at 4.5GHz and Vcore is at 1.31v 24/7. What I would like to achieve next is to have my CPU throttle down in frequency and Vcore when idling and have it jump back to my overclocked speeds and Vcore when on load.

After doing some research I figured out that in order to achieve this, I need to enable EIST/SpeedStep and in conjunction use the "offset" method of setting the Vcore instead of "manual."

I am still confused about what the offset applies to. I read somewhere that with using the offset method Vcore = VID + Voffset. What exactly is VID and what does it effect? I also see something called "Vdroop" being mentioned alot in the forums. Can you please explain this voltage also?

I guess my plan of attack right now will be to enable EIST/Speedstep, keep C1, C3, and C6 disabled, and then set my Vcore to "Offset" instead of "Manual" and then mess with the offset value whether it be "+" or "-". What do you think?

Can you please give me some example values of that to try in terms of the offset values?

Right now I have a 8 hour Prime 95 Blend stable overclock at 4.5GHz with 1.310 volt Vcore using the manual method. So I assume that whatever I do I need to make sure that once all is said and done with EIST/Speedstep, whenever load kicks in it goes back up to that voltage from whatever it was when the PC was idling to maintain the 4.5GHz stability. But I am still unsure on how to do this. Can you please give me some pointers?

Here are my system specs:

Intel i7-2600k Sandy Bridge@4.5GHz
ASUS P8Z68-V/GEN3 PRO
G.Skill Ripjaws-X 8GB DDR3 1600
MSI Radeon HD6970 Twin Frozr III
Thermalright Venemous-X RT
Crucial M4 128GB SATAIII SSD
Corsair CMPSU-850TX 850 Watt

Thank you kindly for any help.
 
Just enable all the power saving features, EIST, C1E, C3 and C6. Enabling some but not others can cause weird frequency and voltage behavior.

As for the offset, it's really trial and error. The offset is added to whatever voltage the chip is requesting at a given frequency - but there is no way to know that requested voltage until you try it. So you'll have to set an offset (say +.1) and then check what voltage that provides under load at the desired overclock. Then go back and tweak it so it ends up where you have the manual voltage. You also want to go with a low-medium setting for LLC, because at high settings the motherboard will add voltage (instead of just offsetting the normal voltage drop you get under load). The result of this is that in lightly loaded situations (like single threaded apps) the CPU might not be getting enough voltage (because LLC doesn't kick in in those situations) and you'll get crashes.

So in short, enable power saving features, set something low-mid for LLC, pick an offset to start with, test it, then adjust the offset as required to get the desired final voltage.
 
Forceman said:
Just enable all the power saving features, EIST, C1E, C3 and C6. Enabling some but not others can cause weird frequency and voltage behavior.

As for the offset, it's really trial and error. The offset is added to whatever voltage the chip is requesting at a given frequency - but there is no way to know that requested voltage until you try it. So you'll have to set an offset (say +.1) and then check what voltage that provides under load at the desired overclock. Then go back and tweak it so it ends up where you have the manual voltage. You also want to go with a low-medium setting for LLC, because at high settings the motherboard will add voltage (instead of just offsetting the normal voltage drop you get under load). The result of this is that in lightly loaded situations (like single threaded apps) the CPU might not be getting enough voltage (because LLC doesn't kick in in those situations) and you'll get crashes.

So in short, enable power saving features, set something low-mid for LLC, pick an offset to start with, test it, then adjust the offset as required to get the desired final voltage.
Click to expand...

Ok, so basically what you are saying is that I can set my Vcore control to "Offset" along with setting LLC to low/medium, and then leave "CPU Offset Voltage" to AUTO and then boot into windows and see what the new load voltage is with my 4.5GHz overclock. Given that I know that I am stable at 1.31 Volts, if I see anything higher or lower than that, I can adjust using the "+" and "-" offsets until I get to my 1.31 stable Vcore?

I've read that its recommended to keep the C3 and C6 states disabled as they ramp down the Vcore when idling and cause crashes. I see alot of people leaving them off when using offset overclocking. Is there a reason why you suggest for me to turn them on?
 
Auto is basically a value for offset (where the motherboard picks the offset amount), so setting that won't really tell you anything about what actual number to put in the offset box yourself (because it is adding an unknown amount to an already unknown amount). You need to fix one of those variables, and the only one you can fix is the offset amount. So put something in yourself (+.05 or +.1 is a good test) and then adjust it after you see what happens.

As for C3 and C6 lowering the voltage, as long as the frequency is also lowered (which it will be) then you won't need to worry about it crashing at idle. If you run a negative offset it might be something to think about, but wait and see if you are in that position first. There are some reports of C3 and C6 causing poor SSD performance, but unless you experience something like that, I'd just leave them enabled.
 
Alright, my plan of attack is to load optimized defaults in BIOS so I can bring my CPU back to stock speeds. Then I will stress test and find out what my maximum load voltage is at stock and then I will bring back my 4.5GHz overclock with SpeedStep enabled and set Vcore to offset and just add enough offset to my maximum stock Vcore to equal to 1.31 volts because I know that I am stable at 4.5GHz with that voltage. Does this seem correct?
 
ExGreyFox said:
Alright, my plan of attack is to load optimized defaults in BIOS so I can bring my CPU back to stock speeds. Then I will stress test and find out what my maximum load voltage is at stock and then I will bring back my 4.5GHz overclock with SpeedStep enabled and set Vcore to offset and just add enough offset to my maximum stock Vcore to equal to 1.31 volts because I know that I am stable at 4.5GHz with that voltage. Does this seem correct?
Click to expand...

Yep, except you don't really need to run it at stock, since the voltage you see there is not going to be the same voltage as at 4.5. The voltage the chip is requesting (essentially the Vid) is different at different speeds.
 
Forceman said:
Yep, except you don't really need to run it at stock, since the voltage you see there is not going to be the same voltage as at 4.5. The voltage the chip is requesting (essentially the Vid) is different at different speeds.
Click to expand...

I see what you are saying. VID changes with different multipliers correct? So in that case what do I need to do with my Vcore to see what the VID is for my 4.5GHz overclock? Do I set it to AUTO? And if so, do I need to change anything else? This is the part that confuses me, how do I find out what my VID is for the 45 multiplier?
 
Yes, Vid changes with different multipliers. The only way to find out the Vid at 4.5 is to set an offset of +0.0. Since the Vcore is Vid + offset, that'll tell you what it is. AUTO is basically Vid + [some number the MB thinks makes sense], and you have no way of knowing what that number is.

However, if all you want is a 4.5 overclock, you can just leave the Vcore on Auto. The board will likely run a higher voltage than is actually needed (so maybe 1.35 instead of 1.31) but it'll be a safe voltage, and most likely stable. And it avoids messing with the offset. Auto works pretty well until you get above 4.6, at which point it starts to really ramp the voltage up.
 
Forceman said:
Yes, Vid changes with different multipliers. The only way to find out the Vid at 4.5 is to set an offset of +0.0. Since the Vcore is Vid + offset, that'll tell you what it is. AUTO is basically Vid + [some number the MB thinks makes sense], and you have no way of knowing what that number is.

However, if all you want is a 4.5 overclock, you can just leave the Vcore on Auto. The board will likely run a higher voltage than is actually needed (so maybe 1.35 instead of 1.31) but it'll be a safe voltage, and most likely stable. And it avoids messing with the offset. Auto works pretty well until you get above 4.6, at which point it starts to really ramp the voltage up.
Click to expand...

Ok, I will set an offset of +0.0 and work it that way. Thanks so much my good sir. I will get to this as soon as this friday night and get back to you with my results. :D Once again, thank you tremendously!!
 
Forceman, what can you recommend I do with LLC, C1E, C3, and C6 when using offset overclocking? Right now with using manual overclocking, I have LLC set to High, (option 3 or 50% in my BIOS) with C1E, C3, and C6 disabled.
 
I had to disable C3 and C6 on my Asrock Z68 board, it caused lockups and BSOD's when overclocking in "offset" mode. When I started messing with "offset" is when my overclock really came alive though, before in "fixed" mode I was only able to get to about 4.2Ghz, in offset, I can hit 5.0Ghz pretty easily, if I want to push alot of voltage.
 
Pitbully said:
I had to disable C3 and C6 on my Asrock Z68 board, it caused lockups and BSOD's when overclocking in "offset" mode. When I started messing with "offset" is when my overclock really came alive though, before in "fixed" mode I was only able to get to about 4.2Ghz, in offset, I can hit 5.0Ghz pretty easily, if I want to push alot of voltage.
Click to expand...

Pitbilly, thanks for your input sir :)

I am also seeing alot of people leaving C1E enabled and disabling both C3 and C6 just like you. I will do the same. I am not sure what to do with LLC however. Can you enlighten me? :confused:
 
I'd recommend running the lowest LLC you can get away with. The higher you set it, the more likely you are to run into low voltage problems at idle and lightly loaded. Plus in my experience more LLC causes more heat. I run a couple degrees cooler with 'regular' LLC and a higher +offset, than I do with 'high' LLC and a lower offset that gives the exact same final fully loaded voltage (as read by dmm).

I theorize that it happens because even though the fully loaded volts are the same, 'high' LLC is actually giving slightly more voltage when not quite fully loaded, say 90% or something, and/or as the load level swings up and down 'high' LLC tends to stay at a higher voltage level longer than 'regular' (I'm just guessing on that part, EE's/gurus feel free to fix my theory). Droop may also play a role but remember my final full load voltage is the exact same either way so I'm not sure how.
 
ExGreyFox said:
Forceman, what can you recommend I do with LLC, C1E, C3, and C6 when using offset overclocking? Right now with using manual overclocking, I have LLC set to High, (option 3 or 50% in my BIOS) with C1E, C3, and C6 disabled.
Click to expand...

As others have said, I'd try to set a lower setting for LLC if possible - try 25% and see if that works okay when you start playing with it.

I have all the power-saving enabled and haven't run into problems, but some people do run into issues with C3 and C6. You can set it up with them disabled if you want, and then try enabling them later to see if you notice any difference. I did some testing with it a while back, and disabling C3/C6 did some strange things with the idle frequency and voltage (it wouldn't go all the way down to 1.6 Ghz and < 1v with them off), but it's been a while so I can't remember exactly what the behavior was. Unless you run into issues, I don't think it matters much either way - whatever works for your system.

You can download Throttlewatch and see exactly what C-state the CPU is in, and the corresponding frequency and voltage changes that those setting cause.

Edit: Also, while a 2600K at 4.5 is a really powerful CPU, that's a pretty "routine" overclock and voltage, so you may not be pushing the chip to the point where things like C3/C6 matter much.
 
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ExGreyFox said:
Pitbilly, thanks for your input sir :)

I am also seeing alot of people leaving C1E enabled and disabling both C3 and C6 just like you. I will do the same. I am not sure what to do with LLC however. Can you enlighten me? :confused:
Click to expand...

Asrock does the LLC a bit different then Asus does. Asrock uses level 1-5 for their LLC I believe, I messed around with it somewhat a few months back when I was tweaking my system, but didn't have much luck with anything below level 3, (which is what I finally set it on and left it there).

As others have said already, I would try it first at medium settings and go from there.
 
Got it guys!

Right now for my stable 4.5GHz I have LLC set to High (which is considered level 3 at 50%) with C1E, C3, and C6 all disabled.

So my plan of attack this Friday will go something like this:

1) Find out what my VID is for my stable 4.5GHz OC.
2) Set my Vcore to "Offset" and add or subtract the right amount of offset to VID to get me to my stable 1.31 Vcore.
2) Leave LLC to "High" and enable C1E with C3 and C6 disabled.
3) Enable EIST/SpeedStep

And I'll give it a whirl and see if I can run stable at this configuration. Please feel free to modify this plan as you see fit, any suggestions are always welcome guys =)

And as always, thank you kindly for all of your help and time so far.
 
2600k @ 4800 MHz voltage at 1.31, this is 24/7 overclock. I benchmark at 5 ghz and this is all done on air.
 
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