Slow Internet Gaming

[cthulhuiscool]

So recently I have been noticing all my network gamess (Left 4 Dead, CS source and 1.6, TF2) and often (not always) it goes extremely slow in a way where it runs perfectly 2-3 seconds and freezes a couple and repeats that way. Also I sometimes get an error (network overbuffer) or something like that. I am not sure if it does that during normal downloads as it is difficult to notice. This does not always occur but on some servers it always occurs (I play a css zombie mod and one server is always like a clipshow) I have tried a neighbors wireless network and tried directly connecting to my router with the same issues and I have no real slowdown in singleplayer games so I don't think the problem is anything with hardware. Does anyone have any idea what this problem is and how I can fix it?