Overclocking i5 2500K problem with LLC

[Moohammad]

hi

i just overclocked my i5 2500K to 4.8Ghz with Z68A-GD55-G3 mobo i set Vcore to 1.36v and disable all power saving settings

but when idle the volt is 1.352-1.344 but with load using IBT it's drop to 1.328-1.336 is this normal ??

and what is the really cpu core is (1.36 or 1.352 or 1.366 ) ??

I have two options for (LLC or Vdroop) low and auto and try both and it's the same ..

[wevsspot]

Welcome to OCC.

 

The cpu voltage drop you are seeing between idle and load is normal. It's also referred to as vdroop. Let's assume that the voltage reduction isn't caused by your power supply's inability to handle the cpu draw at overclocked settings under load (that would be vdrop). There's a difference between the two. Vdroop is perfectly normal and in fact is part of the Intel design criteria. Vdroop is intended to prevent over-shoots of the CPU voltage when your cpu is cycling between various loads and power draws (very simple explanation).

 

There are three ways to offset the effects of vdroop.

 

Method one is to set an initial vcore value that is high enough to result in a cpu voltage under load that is enough to enable stable operation of your cpu at whatever overclocked settings you're using.

 

Method two is to utilize LLC (load line calibration). On every Gigabyte motherboard I'm familiar with, setting the BIOS value to "Vdroop" means that the motherboard power circuitry follows the cpu mfgs' specification for Vdroop. Enabling LLC over-rides the cpu spec. by trying to reduce the amount of vdroop caused when the cpu goes under load. On many motherboards there is a large granularity in how much LLC you can use. Going from low > medium > high or even levels 1 through 10 as examples.

 

As for the actual cpu voltage - the only true way to tell is by measuring the cpu voltage points on the motherboard using a digital multimeter. Some boards have built in measuring points, while on other boards you have to research to find the actual solder points on the board that you would measure to determine the voltage. In my experience the cpu voltage displayed in BIOS is usually the closest to what you would measure if using a multimeter. And, in fact there are some third party apps that measure cpu voltage and you can actually calibrate the voltage readout to agree with what you've measured with a multimeter or what you have observed in the BIOS.

 

To close a rather long post - if your rig is stress test stable with a vcore of 1.36v set in the BIOS and no LLC then you should leave it there and not worry about it. The voltage you're using to get 4.8Ghz is perfectly fine. However, if your rig isn't stress test stable you might consider enabling LLC (and not increasing the vcore setting in BIOS) and re-run your test. LLC level set to low in your BIOS means that the motherboard will attempt to reduce the vdroop to a very low level which may help improve stability.