NBN FW Ping Problem

Just switched over from ADSL to FW NBN. Problem I immediately noticed was a spike/jump in ping when playing games. This never happened on ADSL and our home network is identical to how it was setup when using ADSL (computers are network cabled and wifi not used). There is no packet loss at all but when playing games ping will occassionally spike. For example it will hover around 50ms or so then jump to 100ms. The result is lag/stutter in games. It's very noticeable and was my main concern about switching from ADSL to FW NBN. I'm using the sagemcom 5350 sent by telstra. Again, the connection looks good. Speedtest.net shows 15 - 24mbit download speed and upload of around 4 mbit and we're on the 25/5 plan.