I run four rx 480 with a 750 watt psu
About the GPU miner, best is to stick to the good old Genoil's miner. It supports stratum and gethwork. Depending on what you mine, you'll choose one of them.
But for the AMD R9 390, it is a few percentage point slower than the Claymore miners. So I use the Claymore miners.
But don't Claymore take a percentage or something like that ? I prefer to give tips even if I'm taken more at the end than to be obligated to give a reward.
Claymore take 1% for the Ethereum mining only. So it is worth using the Claymore miner. It is also more stable connection.