Are you referring to GPU rigs??
If so,wrong section..............
Your better off building your own.......much cheaper......
If you can't build it yourself,find a local PC repair shop & ask if they can help you,then if you have any problems later you have a local shop that can help fix it,since they built it
Otherwise you will be hard pressed to get any help from an ebay seller,besides shipping the whole rig back & forth eating up cash........