I know that Amazon's Cluster GPU Instances have ECC memory as mentioned on their blog but there's no mention of other instance types. There's a forum post from back in 2007 that went unanswered. Does anyone know if they're running ECC?
AWS does not comment on this question. The general consensus (based on seeing this question asked on SO, HackerNews, Reddit and so on) is that, unless AWS specifically tells you the instance type is running ECC memory, you should assume it is not.
Although unscientific and inconclusive I suppose this makes sense - ECC is a selling point, and the fact that AWS does not plaster "all our instances run ECC" on their info pages certainly suggests that they are not.