Personal anecdote. I have a Phenom + Asus mobo system with ECC memory in it that has been working fine for years without reporting a single ECC error. And then

Personal anecdote. I have a Phenom + Asus mobo system with ECC memory in it that has been working fine for years without reporting a single ECC error. And then they started. At first there was a correctable error once every few days, then few errors per day, and then almost a constant stream of errors. Fortunately, they were all correctable. From the reported ECC syndomes I deduced that it was always the same single bit lane. That's why only a single ECC symbol was affected and the errors were correctable. I reseated the CPU and DIMMs and the errors went away, and the system keeps chugging on. Not sure what it was, maybe some dust particle getting in a wrong place, maybe some oxidation. Anyway, I can only imagine how much trouble those errors could do if they were not detected and corrected. Especially, at the stage when there was a moderate number of them. I guess when they would become too many, then the system would just crash all the time.