How to connect multiple AMD 7850's to one motherboard

[mehmehspazumweh]

Hello. I am looking to build a GPU litecoin miner and i still cannot seem to work out how people are connecting multiple GPU's to a single motherboard. I currently only have 1 AMD 7850 but i will be buying more over the next few months. So my question is... how exactly are multiple GPU's connected to one motherboard? What cables do i need and how are they connected? I know there are motherboards out there that can house 3 PCIe x16 but these are silly prices. I've seen mining rigs with 40... 50... 60 GPU's! How is this done?! Thanks

 

[lt_dan_zsu]

http://www.google.com/imgres?um=1&hl=en&sa=N&tbo=d&rlz=1C1TSNH_enUS423US423&biw=1024&bih=475&tbm=isch&tbnid=cmYgHIgXpIV_6M:&imgrefurl=https://bitcointalk.org/index.php%3Ftopic%3D29729.0&docid=OwThD9BiGNUTvM&imgurl=http://www.stomped.me/pics/100_0253.JPG&w=2576&h=1932&ei=NjTOUJXIIqHVyAHskYDoDw&zoom=1&iact=hc&vpx=4&vpy=4&dur=388&hovh=194&hovw=259&tx=152&ty=79&sig=112250026798695356625&page=1&tbnh=146&tbnw=202&start=0&ndsp=10&ved=1t:429,r:5,s:0,i:106
From that image it looks like he got some kind of wire that divides the PCIe port into to or more so you connect in more than you are supposed to be able to. I haven't heard of this until now though. I am confused what is but mining exactly?