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P35-S3G not accepting ANY custom CPU frequency/FSB timings, any ideas?

Hi All,
I have Gigabyte P35-S3G motherboard with E2160 CPU  for 3 years and I was able to over clock E2160 from 2GHz to 2.66GHz and higher without any problems. Now I have upgraded to Q9400 and tried to play with FSB and DDR2 settings so that I can eventually overclock Q9400 to some extent. It turned out that with new CPU I cannot use ANY custom settings for FSB or PCIe frequencies.

For example: system boots fine with all settings in auto mode but when I change PCIe Frequency from auto to 100MHz manually, then system double boots, beeps and previous bios settings are reloaded automatically. Same way when I change FSB frequency from auto to 333MHz (8 x 333 MHz, which is default for Q9400) manually, then system again double boots, beeps and previous bios settings are reloaded automatically. In both cases when I go to BIOS after the reboot, FSB and PCIe settings are reverted to 'auto'. I cannot make the motherboard to take even underclock of 8 x 266MHz, it still double beeps and reverts back to auto FSB timing. So basically and motherboard only boots with auto settings and ANY custom setting (even the default or underclock setting) make system to reboot to auto settings.

I have played with various settings, like incrementally increasing voltages for DDR2, FSB over-voltage, MCH over-voltage and vcore to max. I have pushed CPU voltage as high as 1.4 with FSB of 333Mhz but still system reverts to 'auto' as mentioned above.  I have disabled CPU C1E,  CPU TM2,  CPU EIST and HPET support in BIOS  before playing with custom speed and voltage settings. I have used the latest F5 and F6c version of BIOS before attempting custom settings. I have also removes battery from the motherboard to clear CMOS and loaded optimized default values many time throughout the testing process. I have also used relaxed memory timings and over-voltages.

Now I have no idea what I am doing wrong. My question is, has anyone ever successfully overclock a quad core CPU with this motherboard?

Any suggestions or ideas to resolve this situation would be welcome.
Thank you.

Test System:
PSU: OCZ ZX-850  (850 watts - 80 plus Gold)
RAM: OCZ PC2-6400 platinum2 (2 x 1GB) -  part# OCZ2P800R21G
Hard Drive: disconnected
CPU: Intel Q9400  (8 x 333 = 2.66 MHz clockspeed / FSB 1333 MHz)
CPU Cooler: Thermalright XP-90 with Arctic Cooling 90mm fan.
Motherboard: Gigabyte P35-S3G with F5 and F6c BIOs versions.
Video Card: 8800GT 512MB  
« Last Edit: May 12, 2012, 01:18:03 am by Raindrop »