9 Replies Latest reply on Jan 25, 2011 9:57 AM by Yidaki

    2500k stuck OC


      I recently purchased an i5 2500k and have it setting at 4.3ghz.  My asrock mobo can let me change bclk settings in windows and have gotten it to pass 4 hours of prime95 at 4.45ghz.  Yet, no matter how much I put on voltage, it will not boot windows even at just 4.4ghz on 100bclk.  Why?

        • 1. Re: 2500k stuck OC

          BIOS ID?

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          • 2. Re: 2500k stuck OC

            I updated the BIOS to P1.30, and had it at P1.1 and neither do any good.

            • 3. Re: 2500k stuck OC

              and which mainboard?

              • 4. Re: 2500k stuck OC

                Here are my specs -


                i5 2500k

                ASRock P67 Extreme4

                G.SKILL Ripjaws @ 1600 MHz CAS 9 1.5V

                MSi Cyclone GTX 460 @ 905 MHz

                WD Caviar Black 640GB SATA 6Gb/s

                Xigmatek 700W 80 Plus Bronze


                I also have a Xigmatek Baldur heatsink and fan, just in case you were wondering about thermals.  THe peak temp I've seen is 54º C with Prime95 for about 8 hours.  I have noticed that when I monitor individual core temps one core is always ~5º C below the others, and it maxes out at 49º C.

                • 5. Re: 2500k stuck OC

                  Try the new 1.40 BIOS: http://www.pctreiber.net/asrock-bios-downloads?did=223


                  ASRock P67 Extreme4 BIOS 1.40 release notes:


                  1. Update CPU microcode.
                  2. Improve OC capability.


                  Maybe you can give it a try!

                  • 6. Re: 2500k stuck OC

                    Thank you so much!  I'm happy to say that after updating the BIOS, it gave me another option for CPU PLL overvoltage among other things, and although I ahd set the voltage for PLL higher earlier, this somehow broke the 4.3GHz barrier.  Now I'm sitting at a stable 4.7GHz 1.35V OC which maxes out at 63º C in Prime95.  I could go higher, but my real world performance isn't going up enough to warrant the extra VCore.  Anyways, I don't know how to say thank you enough.

                    • 7. Re: 2500k stuck OC

                      That's great


                      Be aware of the CPU PLL overvoltage option, it can damage your CPU (so do people say ...).

                      4.7Ghz with 1.35V is nice, i can reach 4,4Ghz with 1.260V.

                      1 of 1 people found this helpful
                      • 8. Re: 2500k stuck OC

                        I've heard the same, but I made sure to keep the PLL voltage around where review sites keep it in their longevity 24/7 reviews.  I'm just so gald I waited a few months for this CPU, I upgraded from an old Pentium 4 631 HT Cedar Mill OC'd to 4.00 GHz!

                        • 9. Re: 2500k stuck OC

                          I wouldn't think that Intel applied this new option in their BIOS if it wasn't safe. That's for sure. I have also heard abut rumours, where people had 3 identical test setups. One was bumped with high VTT (over 1.6V!), the other one with high memory voltage (1.65V and beyond). Some people said, that the dying of some Sandy Bridge was due to high memory voltage. Intel reccomends 1.425 - 1.575V.


                          My goal is also a 24/7 stable system. I think 4Ghz on each core should be enough for a while - nevertheless, with ~1.3V I can go 4,5ghz.