If possible, buy the same series, ie the same manufacturer if possible, settings genasuo. otherwise, everything is set to the worst case, ie the higher voltage, the worse timings etc pp. But the full assembly must not be straightforward osllte be clear. just because there are slots must all do not work. I would imagine most of you, and if there are problems on the preceed 2x2GB and 2x1GB sell / give away whatever.