tahiti (280x&7970) works perfectly with 10-12sol per card.
390 require a lot of virtual memory - 38Gb on 6 card.
why there is no overclocking effect?
Don't you have invalid solutions? Does the pool stats correspond to your hashrate? And last, why only 10 sols? My tahiti is at least 18 sols, but with invalid solutions. Not a single accepted share. My cards are not overclocked, but undervolted with bios mod. It seems that most of the people have the same isuue.