[ Because we all love anecdotal evidence, here's some of mine ]
And when I called Crucial to RMA the 4 brand new memory modules that were producing errors nonstop (when all 4 were installed, but not when only any 2 were installed) under memtest86 while other vendors' memory in the same system ran rock solid, I was told that it is probably a temperature issue and to run the system with a desktop fan blowing over the RAM. A desktop fan, like a Vornado "air circulator" they meant (and I verified), not a computer-mounted 80mm, 120mm, etc., fan. They refused to RMA the memory because I didn't have a desktop fan blowing on it.
Maybe it was just the crazy folks I happened to speak with that day, and the next day, I don't know, but I stopped buying Crucial memory after that and have stuck with Corsair, Kingston, and OCZ without problems.