I'm looking into building a AMD 8350 Gaming rig. And i cant decide which Motherboard would work better the asus m5a99X evo R2.0 or the asus m5a99FX PRO R2.0. I will be overclocking and running two 7850's in x-fire. I am also open to other suggestions. I cant seem to see the difference between the two boards. There is the x16,x16 vs the x8,x8. but the 2-6 Fps I don't care about too much if it saves me $30.
I have a M5A99FX board. When I bought mine, the 99x and 99fx only had £5 difference so I opted for this. However, in your case the $30 seems quite a lot and so I would suggest you to go for the cheaper one if you only had a single GPU. I think the main differences between the two boards are the chipsets, no of ports, and PCI slots and their speeds. Apart from that they are comparable and both will accept the same CPU's. HOWEVER, since you want to run xfire, I would recommend the M5A99FX because it offers better xfire compatibility.
You could also get the M5A97, which is much cheaper, and then you can get a more powerful SINGLE GPU such as the 7950. But DONT opt for this board if you are planning on xfire.