Yea what you're saying is true, but it doesn't happen the whole time in the game, may be at some parts of the game (A lot of activity at one point) when playing a particular map.
Its also nothing that a GTX 560DF can't handle, like seriously.
Lastly, multiplayer games are usually based on how low your ping is, the better and smoother your gameplay would be.
And as many people use PTCL here on PG, they're ping is pretty much screwed up which in-turns causes all the laggy stuff to appear.
I'am using NayaTel and ping's are usually always below 50, depending when the game is being played.