One thing I found the hard way about RAM is that RAM may appear to be the right spec but have a longer latency, say 2.5 or 3 microseconds (not sure if that is the right unit). If the motherboard demands a latency of 2 then you are effectively overclocking the RAM, so when you use it to capacity, it cooks. Whether in a less extreme case than mine it would malfunction and then appear normal when it had cooled a bit I don't know.