Both your gpu and cpu are fairy weak, soo you can't expect much. Couse each game is different, you'll need to check what gives you slowdown in each of them to be able to customize config for it. Generally EE/GS% reaching 100% means your cpu is too slow for it, if the fps goes down and none of the mentioned reach 100% it's most likely your gpu.
Soo now during slowdowns caused by cpu, go to emulation settings and to get a speedup when EE reaches 100%, use speedhacks or presets(all recommended to begin with, then experiment with the sliders), if GS reaches 100% you could use frameskipping, but that's often buggy and will give you choppy graphics in most cases.
If it's slowing down couse other reasons, most likely gpu, go to GSdx config and among few things you can do here, try decreasing internal res(you should probably stick to "native" to begin with), you can also turn on/off "allow 8 bit textures there" to check if you get a speedup or it slows down even more, and ofc which you should start from, having dx11 gpu and win7, make sure you use DX11 rendering as it's mosly faster. Hardware mode generally is faster, but althrough your cpu is weak, it does have a few useless cores, soo potentially you could get nicer speeds with Software rendering at times when using a few of those cores to render, soo it's good to try to.
You can also read the guide
for detailed info about each option to get some ideas when to use it and if a game is very problematic you can ask, but if above didn't give you speedup, most likely you're trying to run a game which is too demanding on your system, OC cpu could help, but if you bought hexa core cpu with fairy low clocks, I doubt you are into that.