With a 280x and a 290x I'm mining about 1 ETH per day. It still amazes me to see the huge swings in hashrates on both cards.
All my cards are pretty steady with their hashrate.
I'm watching it poolside, the 290x has been as low at 10M and as high as 60M. On the miner they are steady. I just let them run!!
Ahh, yeah poolside it is just an estimate. Are you using ethproxy? It may help even things out a bit.
No, only have 2 miners so I'm using just ETHMINER