Well... after I really updated all Drivers I'd forgot (and geez that were a lot Drivers I didn't thought they may really need an Update...), I don't have Lag's anymore in FFXIV. Didn't tested it in World of Warcraft yet, but it actually worked for me. Don't have Lag's anymore in Instances and in Battles in the open World. Maybe check all Drivers you have for Updates? IDK.