I5-2500k - help with my first overclock

Hello everyone,

This is my first overclock ever so I would love some help with it.

My specs:
Asrock P67 Pro3
I5-2500K with Noctua DH-15 Cooler
8GB Kingston 1333Mhz
MSI GTX970
PSU: Corsair TX650.

I know this isn't top of the line but I don't see a reason to change my CPU just yet.

I would like to have it overclocked to 4.5GHz if possible.
Below are my settings in Bios with three changes: Internal PLL is DISABLED and Additional Turbo Voltage is at minimum – 0.004V, Offset is set to -0.055V and not -0.045 as in the screenshot. With offset set to -0.060V the computer is bootlooping.


With settings as above I went for Intel Burn Test – Stress level: Maximum and 10 passes. It passed without any errors and my temps at the end (after 30 minutes) were: 63 / 68 / 70 / 66.
CPUID HWMonitor was reporting CPU Vcore max as: 1.336V. Do you think it is too high and I should drop CPU Ratio and try to lower voltage more?

Any help would be greatly appreciated. And I’m sorry if my English isn’t perfect (not my native language).

With -0.06 V, you are reducing the Vcore by 0.06 volts. That's why you are boot looping.
You want to add voltage, so try like +0.05 to start with.

Though, I prefer to set the voltage manually instead of this "offset" non sense.
If 70C was your max temps, then according to Intel, you are already at the max temp of 72.6. But, I think you can go higher..

Also turn off that C1E power saving setting.

Thank you for the reply.

I know that I am reducing voltage, isn't that the point with offset? I mean to have lowest possible voltage supplied to CPU + the temperatures are then lower? And I know many people prefer to have fixed voltages but I'm not really comfortable with CPU having the same voltage in windows doing nothing and while playing games.

As for the temperatures, the 70 max was only during stress testing and only in Intel Burn Test. In prime95 or OCCT it doesn't go higher than 65 after ~1 hour. In games, like GTA V it was at max 53 on one core.

edit: sorry, I mean it doesn't go higher than 55 (not 65) after 1h of prime95.

Cylon said:

Thank you for the reply.

I know that I am reducing voltage, isn't that the point with offset? I mean to have lowest possible voltage supplied to CPU + the temperatures are then lower? And I know many people prefer to have fixed voltages but I'm not really comfortable with CPU having the same voltage in windows doing nothing and while playing games.

As for the temperatures, the 70 max was only during stress testing and only in Intel Burn Test. In prime95 or OCCT it doesn't go higher than 65 after ~1 hour. In games, like GTA V it was at max 53 on one core.

edit: sorry, I mean it doesn't go higher than 55 (not 65) after 1h of prime95.

Click to expand...

Yes with offest you can reduce the voltage and temps, but IIRC that doesn't do anything with the energy saving features off.

What you do is find your stable overclock, then enable the power saving features one by one. If you are lucky, your overclock will hold and your CPU will be able to idle...

Now, with your offset settings of -0.045 and such, the CPU appears to not be getting enough voltage to be stable.
You need to either set it to "Normal" offset, or give it some more voltage to be stable and avoid the bootloop you had.

FWIW, I had my i5 2300 overclocked to 3.7 Ghz which needed stock voltage to be stable. 1.26 Vcore.
Find your overclock, up the voltage until it is stable, the reduce the voltage one step at a time until it's unstable. Then increase the voltage by one step and you should be stable.

Here is a nice guide to help you a bit

Ok, thank you for the reply.

I'll try to set a fixed voltage instead of offset and get it stable. Then I will try playing again with the offset.

But I have a question, if you had to guess - @4.5GHz with Vcore of 1.336V is a little bit high, right? This is not a safe voltage to have for everyday use?

Cylon said:

Ok, thank you for the reply.

I'll try to set a fixed voltage instead of offset and get it stable. Then I will try playing again with the offset.

But I have a question, if you had to guess - @4.5GHz with Vcore of 1.336V is a little bit high, right? This is not a safe voltage to have for everyday use?

Click to expand...

I would stay below 1.35 Vcore for everyday.
Keep your temps in check though.

Thanks for your help.
I will try to read the guide you linked and some others but I think I have a bad chip for overclocking. I changed my CPU Ratio to 43 instead of 45 and set fixed voltage of 1.35 and it wouldn't boot, I went as high as 1.45V and it still wouldn't boot! It just said "Machine check error" and then it powered off and then on by itself and again said "Machine check error". I haven't upped the voltage to 1.5 so I reverted to defaults.

Cylon said:

Thanks for your help.
I will try to read the guide you linked and some others but I think I have a bad chip for overclocking. I changed my CPU Ratio to 43 instead of 45 and set fixed voltage of 1.35 and it wouldn't boot, I went as high as 1.45V and it still wouldn't boot! It just said "Machine check error" and then it powered off and then on by itself and again said "Machine check error". I haven't upped the voltage to 1.5 so I reverted to defaults.

Click to expand...

Slow and steady.
Set the stock voltage first, and increase the speed by 100 Mhz.
Keep increasing the overclock by 100 Mhz and testing with Prime 95 (blend for 20 minutes) until it fails. Then up the Vcore and try again.

Keep doing that until you hit 1.35 Volts or temps get too hot.
It takes time to Overclock, but it's fun

I also had a crappy 3570K. Could not get it stable above 4.3 Ghz. Even with 1.5 Vcore!!!
It's luck of the draw with any CPU.