What is the cause of the reject???
gr0bi42, I don't know why you have such high stale ratio. There isn't anything what I'm hiding... What phoenix version _exactly_ do you use? I'll try this version on my machines, maybe there is some change in phoenix...
I'm using the latest version from SVN-repository. It's revision 118. With cgminer 1.5.3 or 1.5.4 I have the same problems. Sometimes it works for some time, but at some moment things get worse...
With poclbm I have an estimated reward of ~0.12. The I use cgminer or phoenix the reward is about 0.08, if the reject ratio is *normal* bad. But sometimes the reject ratio goes up to 80-90% rejects on some of my miners, while others still perform well. It's strange.