Yes because ram has multiple jedec profiles for mobo compatibility. If the ram didn't work it just wasn't compatible with that mobo. That is why mobo manufacturers have a qvl. Ecs isn't good and I would not recommend them. Asus and intel are good and will work with just about any ram. Ram will not overclock itself. The stated speed is just the max it was tested at, not the speed it will default to. It will default to the mobo/cpu default speed.