# overclocking an e8400



## cliffo88 (Jul 5, 2008)

Hi, i have the following setup:

Intel core2 duo e8400 3.0ghz (stock)
Zalman 9700NT cooler
MSI P7N diamond 780i motherboard
XFX 9800gtx black edition GPU
4gb crucial xms2 ddr2 ram
antec trupower 1000w PSU.
Vista home premium 64bit

I have been overclocking the e8400 for a couple of hours and its been nothing but problems, after a lot of effort ive managed to get it stable at 3.6ghz but i couldnt get it stable until i increased the voltage to 1.3V, which seems stupid high for this processor as the box says 1.25V max, temps seem fine in the bios at about 31C so i figured it should be fine.

however i was wondering if you think this is unusual for this processor and weather or not you think i should try and hit 3.7/3.8?

Also what free stress tests should i run for a few hours to properly test stability, so far all i've ran is the Crysis Benchmark tool and selected the cpu bench for about 15mins on high settings.

Any help much appreciated, cheers.


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## Kalim (Nov 24, 2006)

First of all, make sure your RAM is set to loose timings and lowered. Lower the ratio so the RAM is running *well below specification* until you can figure out the CPU limitations. By then you can put it back high again.

So, if your RAM is rated for DDR2-800, run it at DDR2-533 whilst OC'ing the FSB. Keep the timings very loose.

Secondly, the voltage is unusual but not unheard of. Some Wolfdales do require 1.3v for 3.6GHz stable whilst others can do 4.5GHz with that voltage. Batch to batch variation.

Thirdly, the voltage in-Windows may not be real -- it could be higher or lower at the CPU VRM's than what Windows suggests.

Lastly, the voltage limitations of the 45nm are very low since this is 45nm. The overclocks that are high require high PLL/vTT/vFSB/vMCH voltage much of the time. So play about with these voltages to gain more stability. You should aim for sub-1.35v under full load, lower than 60°C full load and around 3.7-4.0GHz in my opinion.

Stress the CPU using this tool. There is no better tool for CPU/RAM stability out for Intel CPU's: http://downloads.guru3d.com/IntelBurnTest-v1.6-download-2047.html
That's the same program Intel uses in-house, just with a different GUI. IT'll show you inside 45 minutes if your CPU is stable or otherwise at a setting. :wink:


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## cliffo88 (Jul 5, 2008)

hi, after doing what you said I have it running stable at 3.8ghz and 1.2-1.36v (as shown in CPU-Z).

I ran the stress test you prompted me to download and it said that my cpu had passed. i'm pretty happy with 3.8ghz so I think I'll leave it at that for now.

Thanks for your help.


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