there is a very good program that detects lag sources
its called COMODO FIREWALL
i suggest you to use it if you have lags...
i had 500 ping when i played in online games , and i coudnt find the source
then my friend gave me the program and it showed exactly what program takes the internet. (in my case it was a wierd virus that appeard in the name "GoogleUpdateBeta"... , if you have it in the task mannager that might be the problam...)
search it on google