Thank you so much for your replies and help.
I did not mean to buy the apu, thanks for pointing that out
There seems to be 7 pci slots on that board, can I not use them all?http://www.newegg.com/Product/Product.aspx?Item=N82E16813157461
What's wrong with my power supply? Why is ot a no no, it is so much cheaper!
Do I need to plug in the power from the gpu and the Molex connectors?
You can only use the pci express slots, that board has 2 x1 and 2 x16. You cannot use the regular PCI slots unless you use a pci-pcie x1 converter card which generally is not a good idea.
About the PSU: Your power supply is about the only thing in your system that can kill it immediately. Do
not skimp on a bad quality supply. Your rig is an investment. This is sound wisdom and you can take it for what it is, but those are terrible power supplies and you have been advised as such. Any vet miner will tell you this.
Your cards appear to have 1 6 pin. With that seasonic PSU, you would do a single 6 pin into each card (4 total), and then a molex -> 6 pin connector on the other 2.