Overclocking E8400 - Struggling to go above 4GHz

I seem to have reach a limit on my cpu
I've had it stable at 4.01GHz but i can't go higher
It is cooled on air.

Anyone else got it above 4GHz or air?
If so any suggested bios settings?

 

I'm just fiddling about with one at the moment although it's water cooled. So far I'm on 4.2GHz with 1.425v but it doesn't seem to want to go higher than that. Luck of the draw really.

Out of interest what temperatures are you getting at 4GHz?

 

Running Cinebench or the CPC benchmarks it goes up to around 65C

 

Have you tried it with Prime 95. I think the temps might be your limiting factor. I'm getting 51ºC in an ambient of 22ºC but it's with slightly OTT cooling/

 

No i haven't but I shall, although i thought that temps only became limiting factors at around 80C. My my old cooler is used to run at 4GHz but at nearly 80C, hence the new cooler.

 

It's a while since I played with a Core 2 and I must have been thinking of the Tcase temp of around 72C rather than Tjunction temp.

 

Looking at the CPC scores I only get a 3% improvement with the system running at 4.2GHz rather than 4GHz. My RAM options mean I have to run it at 936MHz at 4.2 rather than 1069MHz at 4GHz and this affects the multitasking score which I think is affected by memory bandwidth.

 

I could probably do with some faster and larger RAM, 4GB is just so much snappier in everyday use. My RAM is running at 880MHz currently

 

I can run the E8400 @ around 4.4 before the Temps top out @ around 75C.

However I left the RAM stock @ 800mhz, so that might be the reason for the lack of stability. Regardless I'm just running it @ 3.8GHz to prevent instabilities. As far as I can tell with the EP45-UD3P you don't need to up the volts until the 4GHz barrier anyhow.

 

Incidentally (since I also own one) what definition of 'stable' are we working with here? I'm going to start OCing at some point and will take all this info on board, but obviously can't if you're talking "3 hours of gaming" stable and I'm shooting for "6 days of folding" stable.

 

hmmm, I'll start again from 3.6GHz and go up in small increments and keep the RAM nearer 800MHz. I'll see how that goes later.

 

Oh, I'm thinking of several hours folding stable.

 

I always aim for 24 hour Prime95 stable but some people (justifiably) argue that unless you're folding then you're never going to load the system like that in the real world and are happy with a couple of hours.

 

I hear the Biostar is really good for overclocking these CPUs so you're off to a good start already. What kind of voltages are you pumping through the E8400?

Also that's the 9 stepping CPU is it not? My E8500 has 9.5 so goes a wee bit further. Can also unlink memory from the CPU clock on my 680i motherboard which works a treat.

 

You could just be reaching the limit of your chip - before this E8400 I had an E5300, a great stepping, that simply would not go above 3GHz. I knew it wasn't the rest of the hardware in this rig because I dropped my E8400 in at 3GHz, no problems.

Then put it up to 3.5GHz without touching anything.

 

Okay, 3.97GHz without changing any voltages.
Running F@H at full load (I think) and seeing how stable it is.
I reckon I can get 4.1GHz before changing voltages too then I'll go from there.
Adding an extra 120mm case fan to help keep air moving (currently only have a single 120mm exhaust fan)

 

For stress testing use Orthos, or at a push OCCT.

 

I will, currently though need my PC, which is what I'm using now.
I think I am having minor stability issues,
both HWmonitor and windows media have stopped responding which does not usually happen.