Couldn't find a single OC thread in the search on this chipset.

It's not the best for overclocking, but I guess that's the trade off for running SLI.

Still, I've cranked it up from 2.13GHz to 3.10GHz, by raising the FSB bus from 1066 to 1550.
My RAM is brought over from my old system, so it's still running at 667MHz - which isn't helping much.

I can't get anything more above that comfortably, even raising Vcore in increments. Increasing 0.05v, raised the temp about 5 deg C but added little additional stability. Wouldn't last more than five minutes on Orthos or OCCT.

I haven't yet touched the North/Southbridge voltage.

I admit that I need to run at least a half day stress test to consider this 'stable' but so far about 2 hours, it was okay and held up to gaming and benchmarking on Crysis.

Will go for a half day to full day stess test on OCCT and see.

Curious to know what other guys are getting on the E6420.

Any thoughts?

I'm no pro at overclocking, but i assume ur ram is preventing a more higher overclock.
From what i've read u need a ddr800 to overclock to 400fsb.
Take you cpu 1066/1550 divide by four. ur ram fsb divide by two 266/387.
Therefour your ddr667 ram at standard fsb 333 is running overclocked 54mhz already.
If you are using normal value ram... thats a lot already. Might kill ur ram in the long run.
(Btw i heard going above 3ghz is does not show much performance increase, unless u can boost it to near 3.6ghz)

Thanks for the reply raykoh5,

The mobo can adjust dynamically, so I can run 1550 fsb, and just adjust the ratio between the RAM speed and fsb speed.
Means that I can keep it at 1550 on the FSB, and 667 on RAM.

But yes, I admit it could be a problem with having a lower RAM speed. I'll definitely go up to a performance 800MHz stick that can handle 1066 and try again. Maybe having the mobo adjusting the ratio to compensate for slow RAM is preventing a higher overclock...dunno either.

Anyways, it seems that a good OC on a capable intel mobo for this processor is around 3.2GHz, so I'm pretty close. I suppose I can start raising voltages, but I'm okay for now.

BTW,

Raising from 2.13 to 3.1 gave me an additional 15% increase in the CPU benchmark for Crysis, which is my 'real world' test application. I will run it on PCMark05 to compare my results from the previous entry, but I consider that reasonably good considering all other things equal.