So I did a little bit of research on this and it seems like the GPU architecture used in the 340x is a little bit more modern than what is used in the A10 lineup. It may work, but I would not be completely confident in it. The R7-250 and R5-340 have very different specs. Now it may work, but you might be handicapping the GPU. Dual Graphics is a fun tech to play with, but it tends to be a bi specific in what it will work with.