That ASRock is an awesome mobo. Use this psu. You can easily get 4 of those 5870s on there, if you undervolt you can prolly get all 5. Or get 2 of them for the cost of that Rosewill and have a buttload more power. All 6 of the pcie connectors are 6+2 pin (with 5 5870s you'll need 5 of the 8 pin connectors), and the power rating on there is actually the continuous power, not the peak power like most advertise. It also has a 7 year warranty. I don't have 5 5870s, but I am running 2 5970s and a 5870 off the same board with this power supply, a 5970 with 3 5850s on another similar rig, and a 5970 with a 5870 and 2 5850s in a 3rd rig, all of which are that ASRock mobo and that psu.