290x/win7 x64/13.12catbefore(2%-version): -w 256 -tc 20481 -g 1 -I 21 -----> 3.85mhs
after(free-version): -w 256 -tc 20481 -g 2 -I 15 ----->2.75mhs
no way for -g 1/-w64/-w128-parameters - it`s always 2.6mhs or less
PS What are the optimal settings for 290x/290? I still think that the lack off "-I" (crash of miner when "-I" is above 15) is the main issue in reaching more mhs.

Unfortunately, I haven't any 290x card.
Try to raise -g parameter.
I`ve moved x11mod.cl-file to original sph-miner directory - original sgminer.exe(1.2mb size) crashes when is started
So, I`ve replaced original sgminer.exe(1.2mb size) with the sgminer.exe-mod(1.1mb size) - the same result (poor mhs) and got crash when is started with -I 16 or more parameter.