About a year ago I sent back a couple of AMD Athlon 64 X2 CPUs back to AMD due to overheating. The first thing people would think is that the heatsink/fan or case ventilation is the culprit. Upon closer scrutiny, however, one realizes that the processors themselves are overheating. Whatever the reason remains unclear.
The thing is, with the systems in which those two processors I sent back were installed, I tried other processor units and they didn't overheat and the problem disappeared. Only the processors themselves were replaced. When the replacements arrived, only one of the replacement units were used because I ran out and bought a Sempron for one of the PCs without a processor (it's an office PC and work must continue). Now, a year later, another PC with an Athlon 64 X2 is overheating. I replaced its CPU with the replacement from AMD and voila! Problem fixed. Note that before replacing the overheating processor I tried to fix it by cleaning the fan/heatsink and replacing the thermal compound, which didn't fix the problem.
Have there been other similar cases to this? The processor just seems to generate more heat as it gets old (not sure if it's gradual or it just shoots up right away), and in my case, manifested the problem in 7 months, 15 months and 22 months (three processors have met this fate). I don't know if this is a problem with AMD's 65nm tech or some other factor. AMD's no longer selling 65nm chips now but if the problem is not with their 65nm tech, it might carry over to their 45nm chips and soon, 32nm chips.