New Router ping problems?

I just got the new Cisco E3000. I got it all set up now utilizing my gigabit ethernet. However whenever i play a game, and ping the servers to see my if i'll lag in that server or not the ping at first is very high, then i refresh then all the server pings are very low. For example in steam i'd look in servers for left 4 dead 2, all the servers say 300+, then i refresh and all the same servers are like 60 ping and under. I hate having to check twice to make sure my ping is good. What could be wrong?