https://bitcointalksearch.org/topic/cgminer-optimization-procedure-for-hd6870-102376
https://bitcointalksearch.org/topic/hd6870-maximum-hashs-4114
still it's a pain in the ass to try stuff out, since it often nearly freezes my desktop.
I got about 360kh/h top and avg of about 300kh/h over night, when i am afk, but haven't found a configuration, yet, that gives me good kh/h and let me still work on it. But I guess it#s a matter of more tries. Never hat real problems with btc-mining
setting for my best result, if anyone needs it(the worksize of 64 is strange, but it works)
-o http://ltc.kattare.com:9332/ ^
-u turvarya.1 -p x ^
--thread-concurrency 6720 ^
-I 16 ^
-g 1 ^
-w 64