My e8400 has definitely degraded over a period of 4 weeks. I have never gone over 1.360v, and that was idle, 1.32v load was the most vcore it was ever given.

At first it was stable at 4GHz at 1.29v. It passed 8 hours of small & also large FFT orthos, and 30 passes of linpack.

After 2 weeks, I noticed it would only pass 1 out of 5 linpack tests. I had not changed any settings at all, it just went from stable to unstable. I tried altering my vdimm, underclocking my ram, increasing vNB, loosening the PL, nothing worked. Then I remembered I had heard about this degradation, so I upped the vcore from 1.29v load to 1.304v load, and set everything else the way it had been originally. My system was now rock stable.

Another week passed, and I again noticed that I could only pass 1/5 linpack tests. I again changed everything but the vcore, to no avail. I changed eveything to it's original settings, and begrudgingly bumped up the vcore to 1.32v load. Once again it became rock stable.

After 5 days, it again became unstable. Again after trying everything else, I set the original settings for all components, and increased the vcore to 1.33v load. Yes, once again it became rock stable.

I am absolutely certain my e8400 has degraded from when I purchased it 4 weeks ago. I have had to raise the vcore 0.04v (1.29v load up to 1.33v load) in three steps over a 4 week period to remain stable. I have never gone over intel's maximum of 1.3625v, in fact I never went over 1.360v. It has also been cooled with a T.R.U.E since day one, and has never gone over 52*C at any time.

I am irritated at this situation. CPU's degrading in 4 weeks when kept under their rated maximum voltage and kept cool, is very poor, and has never to my knowledge occurred in the past. I'm not sure about basis for this, but I would guess electromigration and physical degradation of the transistors/gates/silicon wafer in the core to be occurring - perhaps intel rushed it's die shrink, and this rapid degradation is the result of poor engineering?