i5 2500k overclock: safe vcore? - Page 2

Quote:

Originally Posted by tw23 


Thanks !

You're welcome!

So here's a general guide on how to set an Offset Voltage with this motherboard. 

First and foremost, the most important thing is to keep the Load-Line Calibration at either High or Ultra.  Using Ultra should be the best option to use, and I'll explain why later.  :)  In addition, both "CPU C3 Report" and "CPU C6 Report" must be disabled inside of Advanced\ CPU Configuration because having them enabled usually results in BSODs or lock-ups when the system is idle.  The reason why it does that is the voltage otherwise goes way too low to keep the system stable while it's idling.  Disabling C3 and C6 prevents the idle voltage from going too low.  It still goes down nice and low, but just not too low.

Anyway, onto buisness.  I mean, business.  The first thing we want to know is what Offset Voltage to use, and whether it's Plus or Minus (there's a selectable Plus sign and Minus sign).  For example, I used a +0.040V offset voltage for 4.8 GHz.  In order to find out what Offset Voltage to use, we have to know what the exact VID is.  I find Real Temp to be very good at showing what the VID is.  To see your VID in Real Temp, click this:

Note: You may need to put load on the CPU in order to see your actual VID.  I recommend using Prime95 Blend for a few seconds in order to do that.

This is mine, so mine is 1.3561V.  Now let's say that I discovered that I need a core voltage of 1.392-1.400V in order to keep my system stable at 4.8 GHz.  That is, I was using a Manual Mode voltage before, but now I want to use Offset Mode.  This knowledge enables me to know what offset voltage to use.  You see, all that's needed is to find out what the difference is between the VID and the desired core voltage.  The difference between 1.3561V and 1.392V-1.400V is 0.0359-0.0439V.  The desired voltage is higher than my VID, so the Plus sign has to be used.  Also, the motherboard can only set offset voltages in increments of 0.005V, so I decided to try 0.040V and I nailed my desired core voltage while under full load!  If I didn't, then I would have tried 0.035V and then 0.045V.  I mean, I would have had to begin fishing a little.

Again, my Load-Line Calibration is set to Ultra (mine is called Ultra High, but the result is the same).  With the Ultra setting, the vDroop should be reduced so much that it's almost non-existent.  Without having the core voltage droop under full load, it enables me to just do the simple math of finding the difference between the VID and the desired voltage, and then using that as my offset.  So this means that the more vDroop there is, the higher the offset needs to be and the more guesswork that would have to be done.

In other words:

1. Load-Line Calibration:  Ultra High
2. CPU C3 Report:  Disabled
3. CPU C6 Report:  Disabled
4. Find out what your VID is
5. Find the difference between your VID and the desired core voltage
6. In the UEFI BIOS, select Offset Mode where it currently says Manual Mode
7. If desired core voltage is higher than VID, then select a plus Offset Mode Sign.
8. If desired core voltage is lower than VID, then select a minus Offset Mode Sign
9. Enter the difference you found into the Offset Voltage field.  Round it up or down because of the 0.005V increments the motherboard uses
10. Save and Exit
11. Check CPU-Z while Prime95's Blend test is running to see if you achieved your desired voltage
12. If not, then adjust the Offset up or down based on how much you need to add or subtract.  So if you previously had 0.040V but you were over by just a little, then you may need 0.035V instead.

It looks complicated and like it's a ton of work, but the actual process is very easy and even surprisingly simple.

Quote:

Originally Posted by tw23 

Also what is the minimum I can do for a 4.6 GHz overclock?

The best way to find out is experiment because it can be very different from one CPU to another.

Quote:

Originally Posted by bumrush 


Awesome writeup. +1
You managed to explain how offset voltage worked properly in a simple, concise post.... Much better and easier to understand than most of the stuff that is out there.

Thank you!

This is fun for me. 

Quote:

Originally Posted by tw23 

I set my vcore to 1.350, and my multiplier to 47 (so I'm running ~4.7 GHz right now ), but CPU-Z (ROG skin) goes up to 1.352 or something like that when I run Prime95.
Is that normal? Will this harm my CPU?

It's harmless and it's normal for the current settings you have set.  This is vRise, the opposite of vDroop.  If you don't want vRise anymore, then lower the Load-Line Calibration by 1 level.

What core voltage did you have under full load when you had a temp of about 80°C?

Also, did you end up removing the heatsink and putting thermal paste in between the pipes?

Quote:

Originally Posted by tw23 


Thank you for your help, btw, I can't thank you enough . I'm very greatful.

You're very welcome!

Quote:

Originally Posted by tw23 

Okay:
1. I'm running 4.6 ghz now because I can keep my vcore lower (like 1.320) and on full load it is about 1.344 max. usually 1.336 on load, but 1.344 when it is being stressed a lot. On idle, it is about 1.328.

I still see vRise.  If you want this to stop, then choose an LLC setting of Ultra.  If vRise is still present, then choose High.  It's safe, but I find it's easier to have no vRise and even no vDroop if possible.

Quote:

Originally Posted by tw23 

2. No, my dad said not to, because I could ruin my CPU (since the thermal paste sticks on to the CPU, right?) and if I take it off, I will rip it off, and might harm my CPU. Is it 100% safe?

If this weren't safe, then we would never be able to remove the heatsink which means we would never be able to upgrade either the heatsink, CPU, or motherboard.  The CPU and the heatsink are indestructible in this context.  Some people on OCN do this quite frequently for various reasons.  So I still recommend removing the heatsink and re-doing the thermal paste application while making sure this time to put thermal paste in between the gaps along the exposed pipes.

If your dad continues to protest, then just do it anyway to prove to him that it's safe.  He has to learn somehow!

Note: it may feel like it is stuck to the CPU, but I guarantee you that you can pull it off without doing any damage to anything.

Quote:

Originally Posted by tw23 

3. Right now my LLC, is on auto, because when I tried your tutorial I failed miserably and I had to clear CMOS lolz.

What happened when you attempted to do it?  Can you tell me exactly what happened in every detail?

Quote:

Originally Posted by tw23 

I've got two more questions if you don't mind:
1. Should I change my LLC, and to what (I'm running 4.6 ghz)?

I recommend using Ultra.  If the vRise is still present, then switch to High to see if that results in having no vRise.

Quote:

Originally Posted by tw23 

2. Do I need to change the PLL? And if so, to what?

Nope, CPU PLL Voltage can stay on Auto.  If you are referring to Internal PLL Overvoltage, then that should be set to Disabled.

Quote:

Originally Posted by tw23 

Thank you so much . I really appreciate it . Thanks.

You're welcome, tw23!