Probably only going to start with one or two R9 290s, and max the case out with 3-ish.
What's the best altcoin miner motherboard that one can buy today below $150. Factoring in power consumption and hash rate.
Here are just a few that have been popping up in my search results:
ASUS P8Z77-V PRO LGA 1155 Intel Z77
Gigabyte AMD FM2+/FM2 AMP-UP Audio OP-AMP USB DAP-UP UEFI DualBIOS ATX Motherboard GA-G1.Sniper A88X
GIGABYTE GA-970A-UD3 AM3+ AMD 970 SATA 6Gb/s USB 3.0 ATX AMD Motherboard
Gigabyte AMD FM2+/FM2 A88X Dual-Link DVI D-Sub Triple Monitor ATX Motherboard GA-F2A88X-D3H
I'm a fan of this one: GA-970A-UD3
You can get 5 cards on the board pretty easily.
I have this board and I can't get more than 3 going at once. Whats your secret?