Monitor and ping

Worland, on Jun 17 2015 - 13:09, said: Ping is far more complex than just your internet connection. In one of our A+ labs, we demonstrate how video cards affect ping. Whoever wrote Wiki's page on ping would really benefit from that lab.

Pretty much any choke point in your machine can delay its reading and response of data coming from the internet. In your case, it seems the monitor was bogging your machine down a smidge. Could be anything from the type of input the monitor uses, to a faulty cable, to leaky capacitors (common in 2005ish era LCD monitors).