not much you can do on the CPU side...
you just take bad WU's with good ones - setting flags won't do
much (because eventually everything goes to general pool)
The only thing you can do here is overclock or go for more cores
6 core or Multiple socket CPU's - 2P or 4P (ie -bigadv flag)
the GPU side is where you'll make the difference with kepler cards and FAH Flags
so until you have a high end GPU that can benefit from it I wouldn't worry