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  1. #1
    Joined
    Oct 2009
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    12

    How to Overclock i7 860 on Gigabyte P55-UD3R

    The last time I overclocked was when all you had to do was bus speed and CPU multiplier. Can some one explain the logic of tweaking all the different options ie. bclk, qpi and how this affects pcie bus and memory. Can someone give me a step by step order as to what settings to change?

    Also, is there a good boot cd to check for system stability ?

    Thanks
    Last edited by dcohen; 10-27-2009 at 09:00 AM.

  2. #2
    Joined
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    Vvardenfell
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    58
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    Re: How to Overclock i7 860 on Gigabyte P55-UD3R

    OK



    BCKCLK is the equivalent of the old-fashioned bus speed. UNCLK (uncore) and QPI run as ratios to it.
    Uncore is the clock for the memory controller - what used to be the northbridge (but not the memory itself, which is a separate control).
    QPI is the chipset (what used to be the southbridge) controller.
    Thus, as you raise BCKCLK the other two will go up, and so will the RAM speed.

    Please don't ask me about the voltage controls, because it will take me a while to remember which is which. By and large though, you can stay with just Vcore (the CPU) QPI PLL (QPI of course) and DRAM voltages for the early parts of your experiments. Later you can play with CPU PLL and CPU VTT!

    The CPU also has a mutiplier, such that BCKCLK x mult = CPU speed. Mine is currently 196 x 21 = 4116MHz for instance.


    Some rules:


    1) Try to stress each bus in turn, so you know the limits. Start with RAM, then go through Uncore and QPI, and finish with BCKCLK.

    2) Generally Uncore data speed should be at least twice memory, and QPI should be twice Uncore - some say x2 +1. So if RAM is 1600, Uncore should be 3200 and QPI 6400 or higher.

    3) With i7, the max you can get Uncore is about 3500, and the max you can get QPI is about 7500, but I don't know for i5. You should aim to be as close to these figures as you can get without exceeding them - or whatever limits you discover.

    4) The max you will get BCKCLK is probably about 205-210.


    With that in mind, raise BCKCLK a little. Note the values of Uncore and QPI, and remember what I said in the rules. Test. Rinse and repeat. If it falls over, lower the RAM divider first. If that fails, look to the other speeds and lower each uin turn until you've fixed it. Last resort is raising voltages.


    M
    Last edited by Meridian; 10-27-2009 at 05:48 PM.

  3. #3
    Joined
    Oct 2009
    Posts
    12

    Re: How to Overclock i7 860 on Gigabyte P55-UD3R

    Thanks for that detailed response. I still have some questions but let me try some things out first.

    Do you have a boot cd you like for testing stability?

  4. #4
    Joined
    Aug 2000
    Location
    Vvardenfell
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    Posts
    10,926

    Re: How to Overclock i7 860 on Gigabyte P55-UD3R

    I just boot into Windows - which is pretty stressful - and then start with something like 3Dmark06. Longer-term testing is with Prime95 on Blend.


    M

  5. #5
    Joined
    Oct 2009
    Posts
    12

    Re: How to Overclock i7 860 on Gigabyte P55-UD3R

    My main reason for a boot cd is that I don't want to have a bad crash in Windows while oc'ing and corrupt my hard drive and Windows installation.

  6. #6
    Joined
    Aug 2004
    Posts
    10,610

    Re: How to Overclock i7 860 on Gigabyte P55-UD3R

    Quote Originally Posted by dcohen View Post
    My main reason for a boot cd is that I don't want to have a bad crash in Windows while oc'ing and corrupt my hard drive and Windows installation.
    Hasn't happened in a long time, well at least not very often since the pci bus has been locked. I still keep my OS on a different partition/disk so if I have to redo Windows I don't lose my data. That comes in handy, but never an OC problem for me.


    "The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
    - Albert Einstein (1879-1955)

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