Help OCing I5 2500k on ASRock Z68 PRO3 LGA 1155

goldyswank

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Dec 27, 2010
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I am new to the ASRock UEFI Bios and I would like some help getting a stable overclock of 4.5 GHZ. I am somewhat experienced with overclocking but I have never worked with a CPU or motherboard with turbo on it. I would like some help navigating the different settings in the Bios and anything else I may need to know about overclocking this CPU. I have a Hyper 212+ aftermarket heatsink with 2 fans on the CPU and the default temps never go over 32c with a 12hr prime test. From what I have read I will try bumping the multiplier to 45 and then tweaking the voltage but I could use some help determining what settings I should enable and what to disable along with what voltages to adjust.

Mobo: ASRock Z68 PRO3 LGA 1155
CPU: Intel Core i5-2500K Sandy Bridge 3.3GHz
FAN: Hyper 212+
RAM: 4x G.SKILL Ripjaws Series 4GB 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800)
GPU: Galaxy GeForce GTX 465 (Fermi) 1GB 256-bit DDR5 PCI Express 2.0 x16
PSU: Thermaltake 750w
 
Ummm...

1. Change CPU multiplier to 45x
2. Save and exit

Once booted up into Windows, fire up Prime95 and use a monitoring program to check what voltage your board is supplying your CPU to hit 4.5GHz -- it should be between 1.3 and 1.35v. If it's higher that that, you'll have to manually adjust the voltage in the BIOS using Offset mode.
 

goldyswank

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Dec 27, 2010
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Should I make any changes to turbo or speed step?
 

goldyswank

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Dec 27, 2010
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I set my multiplier to 45 and then save and exit and windows did not start up. So I used offset mode and set it to +.1v and it seems to be running fine at around 1.35-1.36v I will continue to play with the offset voltage and see if I can bring it down and still keep stable. Although under a Prime blend test my multiplier is sitting at around 41-43 and is only jumping up to 45 very seldom. And when prime is not running my multiplier is sitting at around 16 is this normal?
 
The CPU down-clocking means that some settings need to be adjusted.

Turbo Boost Power Limit: Manual
Short Duration PL: 220
Long Duration PL: 200
Long Duration Maintained: 56

After saving and exiting, boot into Windows and fire up Prime95 again. It should stay at 4.5GHz now.

The CPU lowering to 1.6GHz at idle is normal. Intel designed it that way to save power because the CPU is idling the vast majority of the time.