All these boards will support 3 double slot GPUs and my Audio Card (PCIE). Except for the ASRock the boards are $300+. All the boards run the same chipset and most other stats.
My set up is: SLI GPUs + GPU for a 3rd monitor + Audio card that runs on PCIE
I currently have a EVGA X58 board but i cannot add another GPU because my audio card takes the slot. And i rather have the audio card rather than a 3rd monitor.