Hi! Can you try the older client? It can be found here. If you still experience slower than normal speed, Google Chrome is normally the best route, but you said you experienced lag there as well. Could I by chance ask which server you play on and what country you are from? It is possible that the lag may be due to location.

~Jib

Hi! I figured it might help because I found the older client to help especially with computers like Chromebook. There is another thing I can think of and its not the most orthodox solution, but have you tried running the game on Google Chrome and downloading an extension called "Ad Block Plus"? I am not entirely sure why, but I have found that having the extension called "Ad Block Plus" really helped in increasing the fps for many players.

~Jib