Mining rig with high hashrate

Hi guys,

Thank you for finding time to answer me. I am planning to start building a rig with high hash rate, I am not that good with computer architecture but I understand basic things. Electricity is not problem, I know you will advice me to check for cards that spend less electricity. In my case I need high hash rate rig.

I was thinking to go with R9 295x2 Radeon, is there any mother board that can handle 6 of these cards. Maybe you will suggest me something else, I am open to all advises.