Game Breaking Lag Spikes!!!

Ok so i bought Call of Duty: Black Ops (the first one) on steam because i like the first one better. Anyways, when i play online i get constant 60 with vsync on and 70-90 with it off with everything on high in multiplayer but when i get close to the enemies i get a terrible lag spike and i get killed and when i watch the kill cam it shows my character frozen. My specs are:

Pentium g860 3ghz sandy bridge dual core
MSI HD 7770 Ghz edition
8gb ddr3 1333mhz ram
windows 7

I know its not anything hardware related because even when i get the lagspike my fps doesn't drop at all, which means it must me connection related. But my ping (for the servers i join at least) is about 30-50 which from my understanding is pretty good. It makes it unplayable. Most of my kills are from a distance because it is just painful when i get close to the enemies. It also made me think maybe the were lag switching or something.... but its a dedicated server and it happens on EVER server...