I just hope you don't mouse over that thing in UI that shows the amount of data you're sending or receiving ? :P

While in game press ALT+TAB then ALT+R type resmon. You should see the resource monitor now. Go to the network tab there should be ffxiv.exe in TCP connection then look for Latency column

Also you can PING and traceroute to NA/EU datacenter, in Resource monitor you will have IP of your server.