Hello, recently I bought 4 2 gb 2133 mhz memory. But I have only 4 slot on my M/B. So, I am planning to buy one 8gb 1600 mhz memory and replace one of my 2gb 2133 mhz. However, will it be compatiable? also if it does, can I assign my APU to use fast 2133 mhz ram not 1600? Thanks 😀