The only thing I've needed to change for Vertcoin is thread concurrency. These seem to be the optimal ones for the cards I've tried so far:
R9 290: 24550
7950: 19712
5850: 5120
Just keep in mind when changing Threadconcurrency think about changing Intensity as well. running high intensity on low concurrency can be detrimental
Thanks. I was just about to post about that. I was having very high rejects (8-15% or so) and dropping my intensity from 20 to 19 helped a lot. Would dropping it even lower help on a dedicated mining rig?