Also, it's possible that your ISP is falling behind. Ping really doesn't say much about your connection. Ping is just the time it takes for a single bit of information to travel from your computer through the series of tubes to the server and back again. This is primarily distance from the server because of that whole speed of light thing (why Euro players typically have pings >150) but can also be caused by poorly routed networks by your ISP.
If your ping is normal/low and you're having bad problems like other players stuttering or hit boxes not registering then what's probably happening is your ISP is choking. Try speedtest.net and see what's going on. If your game is receiving 5Mb/s but your download speed is less than that, some of that information will be lost/delayed. So before dropping some cash on new parts, check your connection and router and call up your ISP to see if they're screwing around with something.