Overclocking the i7 920 on a Gigabyte EX58A-UD5

Hey guys, Im a total overclocking noob but I've read through the walkthrough posted on here by Overshocked, I think. And I've also read through this PDF file from GIGABYTE:


There are some things that confuse me. I *THINK* I have bclk stuff down and understand that whatever the bclk is, you x20 and you get the CPU processor speed. So in theory, if I want to achieve 3.8ghz, the BLCK needs to be set at 190mhz.

Now to my system specs:

Gigabyte EX58A UD5 with Intel i7 920 mated to a Zalman 120mm Cpu cooler

Memory & Power supply:

Antec 750watt power supply

Lifetime 12gig ddr3 1333mhz ram

( will i have any problems with this ram or power supply with a 3.8ghz overclock ? )
5 answers Last reply
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  1. The power supply will be fine unless you have several graphics cards and hard drives sucking up power too.

    The ram speed 1333mhz is going to influence your overclock. Memory frequency of 1600mhz or higher would be better. You should be ok though. This is why...

    the BIOS calculation for ram speed is this formula.


    example 1520 = 190bclk x 8

    example 1140 = 190bclk x 6

    The memory multiplier is controlled by you in the BIOS, you can usually set it to 6,8,10, or 12. The lower you set it the closer you can keep your ram to spec or to prevent making your overclock unstable by having too high a frequency. You might be able to overclock your ram above 1333 but probably not much without some hastle.

    Easiest answer, if you havent bought the ram yet choose something else with 1600mhz. If you have bought it then you will need to toy with your BIOS more to get your 3.8 overclock.

    If you are trying to get to a decent overclock and not spend a lot of time on it then you might want to search for this in google "Quick and dirty method for 4ghz aka screw efficiency".
  2. Thanks for you're help man, appreciate it. The ram was already purchased and its already installed so getting another set is out of the question.

    Wouldn't it be dangerous to go over the factory spec of 1333mhz for the ram ? It's still possible to acheive the 3.8ghz cpu speed right @ 1333mhz right ?
  3. Sure its possible. But based on the example I listed you would either be overclocking your ram to 1520mhz or underclocking it to 1140mhz, depending on what you set your memory multiplier to.

    People overclock their ram "safely", and thats fine as long as they know what the voltages are set to in the BIOS. Most ram will allow 1.6-1.65 Dram voltage (aka vdimm) you need to be sure that the qpi/vtt voltage (aka CPU/vtt voltage, or uncore voltage) is within .4-.5v of that. Personally I would underclock the ram by using the 6x multiplier and save myself the time, maybe work on it later on when you are feeling like tinkering with your system. An i7 x58board is supposed to have 1066mhz ram anyway.

    omg! Just occurred to me....
    You won't need a 190bclk to get 3.8ghz, you will need a 181bclk because you will have turbo enabled. Gives you a x21 multiplier rather than 20x. Granted, in the BIOS you will see 20x but when you save and exit it will be 21x. So that means your memory overclock will only be 1447mhz if you use the 8x memory multiplier or 1086mhz if you use the 6x memory multiplier. :kaola:
  4. Thanks for the info man. From all the guides that Ive seen, it says to turn turbo mode off to avoid other complications and avoid the cpu upping the speed/wattage after you've dialed everything in.

    This is all still new to me, Im afraid to try but we'll see.
  5. No worries. A few key points to help and keep your risk low...

    voltages increased beyond safe levels is what will fry your chip.

    to get 3.8ghz you should be able to do it at stock or close to it 1.25vcore (1.35vcore is "max").

    save your settings in bios when you make some progress (hit f12 in main BIOS window to open up 8 save slots)

    when boot up fails and you cant get back to bios dont panic, turn off pc, unplug power source from pc, push Clr CMOS button on the I/O panel behind the tower, then reload your last good settings from the BIOS saves.

    and probably most important, REMEMBER Dram voltage is set to somewhere around 1.6-1.65 the QPI/Vtt voltage must be within .5v of Dram.

    Dram 1.65 then QPI/Vtt voltage ok at 1.175(default)
    Dram 1.7 then QPI/Vtt voltage NOT ok at 1.175(default)

    Its better to keep Dram and QPI/Vtt closer to a .3-.4 difference or less.

    good luck
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