Hi, help with OC E6420

You can estimate your final OC by multiplying out your FSB (333) with your CPU default multiplier (6). In this case you set it to 333x6 or 1998 (the computer rounded it up to 2000) and that is what you get. If you want for example 2.8Ghz or 2800, divide it by 6 and you will see your FSB needs to be set to 466. You should either unlink your memory from your FSB if possible or set it to auto. To avoid weird multiples that might cause stability problems try 400 FSB which mostly closely matches your 800Mhz memory, although this will only give you an OC of 2.4Ghz.

Oc'ing a CPU with a small multiplier means you have to push your FSB around 450 to 500 to get good Mhz on your CPU and this usually takes a very good quality board.

Hi, i just did that, exactly as you said, i unlinked it , set fsb to 400, multiplier to 6 x and it said that the cpu will work @ 2.4 ghz and memory @ 800 mhz, then when i rebooted a warning appeared just @ the first screen saying that i should re-check FSB/CPU/memory something, in CMOS, is there something wrong ? I could of just pressed F1 and continue but i choose to set it back as it was.is it because of the stock cooler or just a warning i should ignore ?

Okey, i set it on AUTO so you can see what it looks like , auto fsb auto ram freq etc.

since when E6420 have 6x max multiplier????

Now I'm having E6400, difference only having 2mb cache instead of 4mb of E6420. The multiplier of both of them is 8(max)

Now i'm overclocking my E6400 with 800mhz ddr2

speed 400mhz,FSB 4x400mhz=1600 (due to quadpump)

final speed: 400x8 =3.2ghz (due to multiplier here)

so my ratio is 1:1

p/s my mobo gigabyte ga-p35 DS4

I think I see what is happening.

Please remember to disable all Speedstep options in the bios. The default multiplier of your CPU should be either 8X or 9X, can't remember which. What looks to be happening is that your CPU is being throttled down automatically by the speedstep controls in the bios and dropping your multiplier down, that is why it is lower than we would expect it to be.

Yes, any overclocking needs to be done without the bios thermal controls getting in the way. Do a google for the default multiplier of your E6420 and than multiply it out again to get what speed you want. Example if its an 8X multiplier and you want 2.8Ghz, than your FSB would be set to 360.

If your multiplier is at least 8X than be careful because setting your FSB to 400 now will give you 3.2Ghz. The E6420 should be capable of this but it will shoot your temps way up and you might even need to increase your CPU voltage to make it stable. You don't want to try either of those options with a stock cooler.

"E6420 has 8x multiplier, 4mb cache, 1066 FSB, clocked at 2.13ghz." Found this googling, i will give it another go later on and post the results, thanks for the help so far.