Memory seems to be a really painfully difficult thing to get in a form that "just works" these days. After having very little joy with non-QVL listed RAM on some recent systems, I got some QVL RAM for the new system I just built.
I just got a DFI board and some G.Skill RAM. The G.Skill is listed in the QVL for that DFI board, and at DDR2-1066 speed. Yet, it turns out, the mobo doesn't pick the settings the RAM is rated at on "auto", and trying to set it manually to the settings that the RAM is supposed to work at is impossible because it's supposed to be 5-5-5-15-48-13. The mobo doesn't provide the option to set tRAS to less than 16, nor options to set tRC and tWR to more than 41 and 8 respectively. Needless to say, 5-5-5-16-41-8 doesn't work stably (errored out after 2 hours of stress-testing). On "auto" settings it seems to set itself for 5-7-7-20-33. That has passed 10 hours of stress testing so far, but the settings seem downright arbitrary. Go figure.
If you want reliable RAM that does exactly what it says on the tin, stick with fully ratified standards (DDR2 up to 800 / DDR3 up to 1333), and even then not from overclocker/enthusiast brands. Everything above that seems to be baseless marketing nonsense, QVL listed or not.
Take what I say with as big a bucket of salt as you like, but I speak from personal bitter experience. What I originally thought was an isolated case of bad luck is rapidly turning out to be a systematic case of vendors' unsubstantiable marketing misrepresentations.
