Perhaps you mean on-line games over the In Internet. What you already have is a good s it gets of Internet gaming at this point in time.
Let me explain. Suppose you and your friends have a LAN party where you meet together in one room and tie you PCs together with a gigabit Ethernet router. In that case, you would have an slight edge over your friends if your computer was a lot faster.
At the present time, the internet seldom gives 6 megabit speed to residential users. I don't know what the technical term for this is other than to say it is a "bottleneck." Additionally, there is a thing called "latency", which can not be improved by a faster PC.
Let me repeat. If you have a gigabit network, you have a slight advantage with a PC that is a lot faster than then others. It is like drag racing. Lot more power, slight advantage.
