Depends on how forgiving you are to the "compatibility" situation. If you're fine with setting your own memory settings when the XMP profile doesn't work properly, you dont have to care about what the QVL says. If XMP profile must work, buy according to the QVL and not a single letter or number different from what the QVL says. Most of the time kits that arent in the QVL but rated for reasonably speeds (say 3600 CL16) still work fine, but I'm not taking the risk for strangers.