Since the first reports of Intel's overclock lock, the web has been buzzing with speculation about what Intel did and how to fix the lock. There has been so much misinformation, partial truths, and downright confusion regarding the lock that it's time to set the record straight.

Asus and Abit have been most successful so far in finding ways around the lock, so we spent some time with both companies to determine what they have found and how they are bypassing the lock. How do we measure success? It is simply a matter of performance. Abit has managed to produce a 925X that is capable of a 258 CPU Frequency.

Click to enlarge.

Asus has enjoyed even more spectacular success. With their latest BIOS revision 1.04 and higher, Asus is now reaching our CPU limit of 278-283 CPU frequency. This is confirmed with a SATA hard drive and PCIe video card, since you will see there is much more to the story than Northbridge voltage.

Yes, Virginia, There IS an Overclocking Lock

The overclock lock is very real on the Intel 925X/915 chipset. Sources close to Intel have confirmed that the 925X/915 chipset was designed with a 10% overclock limit as a design parameter. This is not a simple lock loop, but involves several components according to Engineers at Asus and Abit:
  1. PCI Express floats in the Intel 925X/915 chipset. PCIe frequency exceeds the capabilities of PCIe cards at about the 10% overclock level. Neither Asus or Abit or any other manufacturer that we have talked with has been able to effectively lock the PCIe frequency in the new 925X/915 design. This is the major roadblock to overclocking on the 925X/915, as any attempt to lock the PCIe frequency limits overclocking.
  2. The Northbridge and Southbridge link frequency also floats with the CPU frequency, and since link frequency is monitored at startup, values higher than 10% cause system shutdown. It is true that increasing the voltage to the chipset increases tolerance in this area, but you only gain about 10 MHz to 15 MHz by applying voltage (CPU frequency can increase from 220 to 230 to 235), since the PCIe and SATA issues are not corrected.
  3. SATA must be fixed at 100 to function, but the SATA frequency is also influenced by the link frequency. SATA drives simply disappear when the link frequency exceeds the 10% overclock. This can be extended with a bit of voltage, but voltage is not a fix for this issue either.

Breaking the Overclock Lock
Comments Locked


View All Comments

  • jiulemoigt - Saturday, July 24, 2004 - link

    I did have to laugh at #5 "Because of DDRII and the hugely overclockable Prescotts, the potential for massive Intel overclocks without extreme cooling and wads of cash would be huge." I remember the last space heater we were told would be a great thing, I think it ended up with a vacum cleaner nickname... DRII will not be faster than DRRI until they get it to the point DDRI is at now. and prescot is the reason intel requires mobo marker to design the mobo with a bolt on heatsink design... Intel survives on marketing along at this point.
  • gimper48 - Wednesday, July 21, 2004 - link

    Wes, Thanks for the response man. Yeah I see what you mean. I didn't take it the same as you I was interpreting it differently. I do not see it as an argument only as a need for more testing.. Peace,
  • Wesley Fink - Tuesday, July 20, 2004 - link

    #12 & #13 - I am not going to get into an argument with HardOCP, but I stand by what is posted here. I have read the [H] article and there is absolutely nothing in the article which proves otherwise to anything posted here.

    All of the testing here was with a 520W 24-pin Power Supply as already stated in the article. We found the 24-pin high-power solution with 6800 Ultra long ago - it is not a new revelation. We also reached 258-260 with the 6800 Ultra and 278 with the ATI X800XT.

    The highest result shown at [H] was 255 with either card, so the results there were not even in the same ballpark. In fact they didn't even reach the limit we found with the Abit AV8, let alone enter the new territory from 260 to 278 that is available with the Asus.
  • gimper48 - Tuesday, July 20, 2004 - link

    I forgot to include the article that the comments are refering to
  • gimper48 - Tuesday, July 20, 2004 - link

    This is what one of the reviewers at had to say about this article and from what I read it seems true. More testing is definitely needed.

    Originally Posted by gimper48

    This gives some interesting insite to the overclock lock.

    And there are some things in there as well that I think are just wrong. I think his #2 statement is incorrect and so is #3. I have proven different here on our test equipment. We are OCing far beyond his 10% with no tweaks at all with a retail CPU. We saw the same issues with the engineering sample CPU.

    The SATA does have a lot to do with it though. And I do agree with his statement that ATI seems to be more tolerant, at least on the newer VPUs.

    It looks as though one thing is for sure, solid OC boards from "everyone" is not going to happen on the 925/915 front. With the latest Asus BIOS, our OCs actually got worse not better. There is still a lot of half-truths everywhere on this. That is one reason we did not get into theorizing explanations that we were not sure of backed up with limited test data using just engineering sample CPUs.
  • gamara - Monday, July 19, 2004 - link

  • dvinnen - Monday, July 19, 2004 - link

    #6 The reason for the multiplier lock was not to limit overclocking, but because some people were abusing it. They would set the multiplier of a 2000+ (or any proc) higher and sell them as a higher rated processor. There was a lot of these conterfit processors floating around last year so they had to lock it.
  • tfranzese - Monday, July 19, 2004 - link

    I was already planning on an AMD64 system once PCI-E comes out w/nForce 4 chips. This just solidifies that decision at least till the fall/winter.
  • mindless1 - Monday, July 19, 2004 - link

    "goodbye until you clean up your act"

    It'll happen alright, for each and every customer who shuns intel because of this... including me.
  • MadAd - Saturday, July 17, 2004 - link

    #1. "goodbye until you clean up your act"? Nah its just not going to happen. The best we can hope for is that the Intel enthusiast crowd only buy the Abit/Asus unlocked boards and put a sour taste in the finances of other mobo manufacturers that did stick to the reference design.

    Lower sales of boards, lower growth, less willingness to develop/support every sub version, less willingness to licence from intel at all yadda ya .... however if the market share of enthusiasts is as small as some make it out to be then we dont really have a choice and intel wouldn't even notice if we did say "goodbye until you clean up your act"

    Even tho some see Intel as the evil leader and AMD the underdog, I find it uncomfortable having no choice in a market of anything, even an AMD only choice.

Log in

Don't have an account? Sign up now