Anyone with knowledge of LGA 775 C2D overclocking and maybe even the 790i chipsets?

Hi there.
I have a problem with overclocking my C2D E8200 on my 790i P7N2 board. But since it's quiet old, I am not sure where to find people that have knowledge with overclocking on these.
Not the P7N2 in specific (because nobody bought it...) but with the 790i in general.

I tried overclocking a bit, but once I hit anything above 1480 MHz, my system simply won't boot anymore. I played with my voltages a bit but I couldn't fix this so far.
In all OC threads about the C2D you read things along the lines that you can easily hit 400-450MHz FSB without even touching any voltages. And here I fail at getting above 370 MHz.




C2D E8200

2x 4GB DDR3 1333MHZ Team Group Elite Ram

Scythe Ninja 2

Enermax Modu82+ 425W

Most bios settings:
D.O.T. Control (1 - 15%) [disabled]

Intel EIST [disabled]

System Clock (Auto, Linked, Unlinked) [unlinked]

Adjust DRAM Frequency

Adjust CPU Ratio [Speedstep technology must be disabled]

DRAM Timing Mode (Auto / Manual)

PCI-E Frequency (100-200 Mhz) [100MHz]

MCP PCI-E Frequency (100-200 Mhz) [100MHz]

CPU Voltage 0,0125 - 0,3875 [+0,025]

DRAM Voltage (V) 1.50 V - 2.40 V [1.55]

SB Voltage (V) 1.525 V - 2.000 V [1.525]

NB Voltage (V) 1.225 V - 1.600 V [1.35]

PCI Expander PLL Voltage 2.551 V - 3.265 V [2.551]

DIMM Memory Reference Voltage 0.485 V - 1.200 V [auto]

Memory Terminator Voltage 0.485 V - 1.200 V [auto]

CPU GTL Reference Voltage 0.779 V - 0.801 V and 0.803 V - 0.828 V [auto/0.817]

NB GTL Reference Voltage 0.709 V - 0.735 V and 0.803 V -0.831 V [auto/0.817]

FSB Terminator Voltage 1.056 V - 1.313 V [auto/1.2V]

SB Sleep Mode Voltage 1.374 V - 1.660 V [auto]

Spread Spectrum (Enable / Disable) [disabled]

Excetute Bit Support [disabled]

HPET [disabled]

[] = values I set.

Exact CPU and NB GTL values vary depending on the FSB Terminator Voltage, but it always remains with two "zones".

Tried 1520 FSB (and values slightly above and below) and it wouldn't boot at all, even with increasing:

RAM 1.6V

CPU +0.1V (!)

SB 1.6

NB 1.45

VTT 1.21

PCI PLL 2.602

For the beginning it would be good to know if there are any people around that could help me or if you know good forums with active people that might could help me. :)
4 answers Last reply
More about knowledge lga 775 c2d overclocking 790i chipsets
  1. Chipsets are like CPUs - some will overclock better than others. It's possible yours is just a bad overclocker. Having said that, did you try increasing the Northbridge/Chipset Voltage (no idea what it's called on nForce chipsets, but on my Gigabyte P45 board, it's listed as "NB Voltage"
  2. I updated the post above with Hardware in the first Spoiler and Bios options in the second spoiler.

    I started at a NB voltage of 1.35V and even went up to 1.45V at one attempt.
  3. I'm assuming you mean it just won't POST above 1480MHz? Have you tried just whacking it up to 400MHz? One of my boards had a weird thing where it wouldn't POST with the FSB set to 345-360MHz, but above that it was fine...

    Beyond that, I'm not really sure... It sounds like either the CPU or NB is a lemon when it comes to overclocking. Have you been able to OC a different CPU in that board, or that CPU in a differnt board before?
  4. That is correct, the monitor stays black, it won't POST and I have to reset the BIOS.
    I will try that in a moment and report back.

    And no, I haven't since it's the only CPU and board I have. :)

    Edit: Wow, I think I am going nuts! :pt1cable:
    1500 to 1600 MHz.. nothing.
    1620 MHz.. POST... Windows! :heink:

    Some question: In most guides they say you should increase your FSB by 5-10 MHz at a time.. I assume they mean the raw FSB and not the quad pumped value huh? That ~150MHz hole equals around 40 MHz...

    At least I know that my board isn't coming straight out of hell. Now I can turn down the voltages again and see what's the minimum requirement to get this thing booting and then check if I can get the FSB 405 MHz stable. Then I will continue from that point. :D
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