E6400 Overclocking Advices !


I just spent the last 5 hours trying to figure out the best settings to overclock my cpu.

Motherboard : ASUS P5W DH Deluxe
CPU : Intel Core 2 Duo 6400 ( 2.13Ghz )
Ram : Kingston KVR667D2N5k2 2x1g DDR2 PC667/PC5300
Graphic Card : NVIDIA GeForce 9600GT (note : this was purchased 1.5 year ago, so not looking to upgrade this )
Hard Drives :
1 x WesterDigital WD2500JS ATA 250GB 7200 RPM 8MB Cache SATA 3.0Gb
1 x WesterDigital WD2500KS ATA 250GB 7200 RPM 16MB Cache SATA 3.0Gb
Power Supply : Antec Smart Power 2.0 SP500 ATX P4 500W 20/24Pin
Case : Antec NSK6500 Mid Tour
OS : Vista 32bit

After slowly upgrading the fsb little by little, i've been able to reach 2.9Ghz so far, fsb set at 363mhz ( x 8 multi).

I didnt have to play with the vcore voltage ( i couldnt do it even if I wanted to, because the setting is "locked" at auto in bios, i cant switch it to manual... )

I leave my ram setting to "auto" in bios and this gives me a 4:3 ratio ( using cpu-z to see that ). So this means my ram is underclocked right ?

The speed increase is very noticable, especially loading windows / startup apps.


Right now I am using the stock cooling that came with the cpu, I use core temp to check my temps and while running about 30 minute of benchmarks ( 3dmark06 + pcmark05 + sisoft ) the max temp reaches 64celcius

After 6 minutes of Ortho's Stress CPU with Gromacs Core , my temp reaches 69Celcius. I let it run for 3 more minute and the temp stayed at 69Celcius.

I then stopped the gromac test, let the cpu cool down a little ( idle/internet browsing temps are in the 44-50 range ) and then started the regular ortho small FFTS stress cpu... Within not even 1 minute I get an error !!! Same things happen when I run the torture test from Prime95 , the small FFTs test fails, but the Blend test works.

I had tried these tests with my cpu at 2.8Ghz and 2.66Ghz and they were running fine. Temps were about the same.


So that is where I am at right now, not quite sure what to do next concerning the Ortho error . My goal would be to get to 3.0Ghz. I know i should be getting an aftermarket cooler, I will soon, along with 2x2gb ddr800 sticks.

I dont think the issue for now is the temperature since the test fails very quickly without temps getting high... maybe there is not enough voltage, but i dont know how to change it with my p5w dh deluxe bios...

Also, concerning the ram ratio, right now as stated before i think my ram is underclocked, is this an issue, what do I need to do about that ?

thanks for your help !
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More about e6400 overclocking advices
  1. The E6400 may not be the best to overclock using a stock cooler. It has a thermal specification of only 61C and TDP of 65W. The E5200 and E7300, for example, are both 74C and 65W. The more you stay over this 61C threshold, the less likely you'll have a stable overclock.

    Idling in the 44-50C range is also too high. It gives the processor no room to move. It has to go from doing nothing to maximium load and is given only 11 to 15C to operate in.

    Something with a 74C spec can be run at the temps your getting. Installing an aftermarket cooler will help with temps. DDR2-800 will also help the overclock at or beyond the speed you currently have.

    If you can get it back under 40C at idle, that would be a good start.
  2. The temperature will not give you that error, though it is high for that processor. my guess is that since you couldn't change your voltage, that your processor is just starved for power. since it worked fine at the lower speeds it looks like you just hit the wall for that processor at that voltage. but, it is just a guess, it is overclocking after all.
  3. Really...? 61C is supposed to be my MAX temperature ? I thought that Intel were just being very conservative. I saw in a lot of forums people saying that as long as you are under 65C it should be ok...

    Does the 61C thermal specification correspond to the "Core Temp" Software temperatures ? I have also used "Real Temp" and the temps are very similar ( +/- 1C )

    What habout the FSB : RAM ratio ? if I want to have a 1:1 ratio I need to set my fsb to 333mhz right ? Would that be better for overall system performance ? My core speed would be 2.66Ghz instead of the 2.9Ghz I currently have.

    Once I buy the new HSF and DDR800 ram to replace my current DDR667 ram, then i'll need to set the FSB to 400 to run in 1:1 ratio right ? That would mean a core speed of 3.2Ghz !!! i'll surely need to be able to increase the voltage for that... but how !?
  4. louno said:
    Really...? 61C is supposed to be my MAX temperature ?

    No, it's not your maximum temp. Take it as if you operate at this temp or less then you should have no issues with heat impacting on system performance.

    The more you go over this the more likely heat will become part of the failure equation. Under this threshold heat can be dismissed as causing any problems.
  5. Your 4:3 ratio means you are underclocking your RAM. I am not familiar with Asus motherboards, but change your RAM setting to "Manual". You should see several multipliers or "strappings" available. Choose the "2.00B" (or whatever it is called) one.

    Now your memory speed will be twice the FSB which is what you need to run 1:1. There's no real gain to running your RAM faster.
  6. jsc said:
    Now your memory speed will be twice the FSB which is what you need to run 1:1. There's no real gain to running your RAM faster.

    if my memory is twice the FSB it will be overclocked then... I have ddr667 ( 333mhz) so i dont think it can support 726mhz ( 363mhz x 2 = twice the fsb ) thats impossible... I dont think I understand what you mean... ?
  7. louno said:
    if my memory is twice the FSB it will be overclocked then...

    No. If mem clock is twice the FSB frequency, you are running 1:1. With DDR2-667 RAM, your RAM is running at rated speed.

    And, yes, at a mem clock freq of 726 MHz, you are OC'ing the RAM a little. If your system is stable, don't worry about it. If it's unstable, you can do one of three things. You can relax the timings a little, or you can raise the RAM voltage a tenth of a volt or so. Or third, you can decrease the mem clock, but that will cost you some performance.

    If I had memory stability problems, those, in order, are the thee things that I would do.

    You said that you are failing the P95 small fft's test. The small fft test uses only the CPU. If it's failing, you have a problem with your CPU settings.
  8. I am thinking about getting either of those memory modules :
    - Kingston HyperX PC2-6400 4GB 2X2GB DDR2-800 CL4-4-4-12 240PIN Dual Channel Memory Kit
    - G.SKILL F2-6400CL4D-4GBPK PC2-6400 4GB 2X2GB DDR2-800 CL4-4-4-12 240PIN Dual Channel Memory Kit Back Ordered
    - Mushkin XP PC2-6400 4GB 2X2GB DDR2-800 CL4-4-4-12 240PIN DIMM Dual Channel Memory Kit Back Ordered

    I selected those because they all run at 2.0V or lower ( g skill is the best at 1.8-1.9 )

    Now I want to overclock my cpu to the maximum possible while spending minimum possible... i decided to do so instead of upgrading my cpu so I need a HSF, I initially selected this one :

    - Arctic Cooling Freezer 7 Pro REV.2 CPU Heatsink Cooler LGA1366 LGA1156 LGA775 AM2 AM3 W/ 92MM Fan
    Because it is apparently pretty quiet ( which is important ) and cheap ( also important ), but still pretty effective too.

    However, I am not sure that this fan uses the best design for my case... The fan is mounted on the side of the heatsink, not on the top like the stock cooler from intel, and my case has somekind of wind tunnel right over the cpu, to draw fresh air directly from outside the case in.

    Here is a picture :

    different views here

    I guess the airduct is not a big issue ? i could remove it and instead put a small fan that would send fresh air from outside directly on to the cpu ? Not sure if this would help or if i should keep the air duct...

    In anycase, my question would be, what HSF should I get ? Is the artic cooling freezer 7 good enough ? are there better alternative that are just as quiet and cheap ( or slightly more expensive )...

    Thanks !
  9. I know that posting here is a bit silly seeing as this thread is so old but I'm trying to get my E6400 past 2.6GHz using an MSI P31 Neo and it doesn't POST when I up the FSB by 10MHz. Current= 333MHz x8.

    Anyway, I have that cooler (I think it's the 1st revision though) and it's alright but if you've got a CPU fan duct get one which has an upwards facing fan. Although I'm sure you got a new cooler almost a year ago...
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