Hi. I've a Sapphire Pure Mini E2-1800 MB, and I'll buy an AMD Radeon HD 6770 or a HD 7750. I don't know if the integrated processor on the motheborad could be enough for one of those GPUs, but currently I don't have much money for buy another more powerfull.
So, what processor do I need at least? Or is the E2-1800 enough?
Sorry about my bad English and thanks for your answers.
I think if it were me, I would first try the integrated HD 7340 at the resolution of your display and see how it performs. Before you can add a discrete card in dual graphics mode, you will need to find out which one(s) is supported. I doubt that the two you mentioned above would work in dual graphics mode with the HD 7340.
Of course, you can always disable the integrated graphics and use just the discrete card alone for graphics. In that case you can use whichever card you want as long as the PSU can handle it.