I simply don't get this 8.5m 280x results. I've downloaded the latest cgminer, tried every setting I've found here and can't get it above 7.6m. w7 x64, catalyst 14.1, gpu/mem 1055/6000, --vectors 1 -I 8 -w 256 --gpu-powertune 20 --no-submit-stale => 7580
Try increasing your engine speed, add -X 105 and enjoy !
Ask for details at #HeavyCoinPool@freenode, very helpfull lads there
https://kiwiirc.com/client/irc.freenode.net/HeavyCoinPoolI think you need to downgrade to Catalyst 13.2. On my 280x I get now 9Mh/s with this config -I 8 -g 1 --gpu-engine 1203 (280x becoming unstable between 1190 - 1220, need to test different speeds).