Use ubuntu 12.04, 14.6 beta drivers( install through gui), latest sgminer v5.
I use r9 280x's and works a treat. Don't bother with Ubuntu 14.04 - spent over a day trying to troubleshoot. xubuntu 12.04 I was up and running in under an hour.
Hmmm, thanks for the reply. It's my main machine so I dont want to downgrade to 12.04...
You've made me realize that I installed the wrong version of sgminer... I meant to grab 5.0, I thought I did until now...
Maybe I'll try sgminer 5.0 & see if that helps at all.
Thanks again