My apologies to everyone on this thread, especially cadaveca, for ever doubting the degrading E8x00 processors issue. The problem is real. Now we just have to find out what a safe maximum voltage should be. Based on the Intel docs I'll be sticking to a maximum of 1.40 volts with my new Wolfie and keeping a close eye on any degrading of performance.
I've started testing with my IR thermometer pointed at my new E8400. I didn't want anything getting in my way of some accurate temp readings so I pulled off the heatsink for a direct shot at the cores.
Anyone that lives in fear when their CoreTemps hit 70C don't need to worry. That's nothing!
When I tested my previous E6400 I found that the readings from my IR gun pointed directly at the IHS were exactly equal to what CoreTemp was reporting from about 47C to 85C where it would begin to throttle.
My E8400 is different. I've seen some users reporting maximum CoreTemps of 70C. When CoreTemp reports 70C for my E8400, the IR gun is only showing an actual temperature of 60C. At lower temperatures the difference approaches 15C. I think this will make a lot of sense for anyone that has gone from dual core Conroe to dual core Penryn on the same board.
The other test I did was I ran my E6400 and E8400 at the same MHz and core voltage. With a small hand held high speed fan pointing at the cores, the lowest I could get down to with my E6400 was 47C as reported by CoreTemp and the IR gun. The 45nm E8400 is smaller and more efficient so common sense says it should run cooler. CoreTemp was reporting 57C during this test but the IR gun was only showing 42C. 5C cooler makes logical sense. Penryn running 10C hotter than Conroe at idle makes no sense.
From this I would have to say to take the absolute reported temperatures based on the on chip sensors with a grain of salt. Intel does not document these sensors being used for that purpose. All of the chips may have a similar temperature curve to what I found but there is no guarantee of that. The on chip DTS was designed for thermal throttling and for showing distance to the throttling point which CoreTemp reports correctly. Just keep in mind that 50 units of headroom until throttling does not exactly translate to 50C of headroom.
Better yet, just forget about temperatures. That's the least of ones worries with these chips. There's a huge amount of temperature head room, even when grossly overclocked. With Penryn, it's voltage headroom that people need to watch. Sorry for getting off topic but I thought this is info that overclockers need to know. I plan to start a new thread tomorrow with more pictures and details. Hopefully if I haven't damaged my new chip too bad I'll be back with a nice OC in the near future.
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