I'm running a E8400 on a EP35-DS3L. I had a stable OC @ 3.6Ghz with stock voltage. I went to bring it up to 4.0Ghz and got fail after fail in Prime95. I played with every setting, RAM is at MAX voltage and locked into solid timings.
When I finally got 4.0Ghz stable with Prime95 the bios voltage was up to 1.4, which is pushing my comfort zone. CPU-z is reading the voltage at 1.344 and Speedfan at 1.34, should a vdrop be this large?
Max temp in Speedfan is at 60c and RealTemp 53C, so I don't think I'm really over volting, am I?
max limit on the E8*** is 1.45, but I want to stay well below that since this is 24/7 OC and I want to get max life and stability out of this setup. My RAM is rated to 2.2v and thats what I have it set at.
I have a GA-P35-DS3L (I curse Gigabyte tech support now for being lying a-holes) and a 2180, and the vdroop on that is pretty huge, too. I set it to 1.44v in the BIOS, and end up getting 1.348v actually getting to the processor. I don't think you should be too suprised by your vdroop, though.
There is a pencil mod out there to reduce the vdroop, though, if you want to try it. A quick google search should find it.
the limit as set by intel to get the rated lifetime is 1.36v but hey your not going to keep it for 5 years are you. i have my e8400 at 1.53v to get a 24/7 stable oc at 4.44ghz. and i might swap it out by xmas. just depends how long your going to keep it for, more than 2 years id stick to the intel max vcore.