As said, you Crossfire AMD, not Sli and boards don't always do both. This is why you should always list your parts. With an A series APU you really don't have the CPU power, your cpu might even be holding back your single 380x. Generally a single stronger card is a much better choice than sli/crossfire. Not all games support it, some that do don't work well and it produces a lot more heat and power consumption. However with an APU I think you need a cpu upgrade at the same time as your GPU