I am getting 323.5 Mhash/s with my Sapphire 5830 using Phoenix w/phatk and all of the enhancements to kernel.cl. Running 11.5 drivers I think with 2.4 SDK and its overclocked at 1020 core, 300 mem. Stable at 59c with the fan set at 70%. I think I have squeezed every last ounce out of this card. I can overclock more, but the gains aren't super impressive for the risk of downtime due to a crash. Been stable on this clockspeed for over 3 weeks.
phoenix -u http://xxxxxxxx:firstname.lastname@example.org
:xxxx/ -k phatk DEVICE=0 VECTORS BFI_INT WORKSIZE=256 AGGRESSION=12