Blender Modeling High Mesh

[Rapture]

What does it take for computer specs to support 10-20 million polygons. I can barely get up to 5 million and whenever I move my viewport (sculpting is sluggish), my FPs goes to 0-5 fps. I've read in a few places to help optimize it like Smooth Shading and Display Only Render or Hiding some of the model (I'd rather look at the whole thing.)
Is their any other optimization I'm missing?

I've seen people on youtube go to 8-12 million with no problems. But all they can tell me is that someone else says this computer is good for modeling. (store)

Some specs...
560ti Video Card
8 Core 3.6GHz AMD
12g of RAM.