I currently have a 7 sapphire nitro rx 480 8gb rig running off of an msi gaming 5 mobo. If I were you, I'd invest in a 6x gpu rig and then build another one on top of that if you want more mining power. I'm currently building a new 6x gpu rig and one of the cards will be moved from my 7x rig to the new one so they both have 6x each. Also, save yourself a huge headache and use windows 10.