If you have lag problems (a freeze every second or few seconds), I might have a fix. The problem for me was exactly what bergv said: a network request to some file called "as.ini" about once a second. The fix was to block the address in uBlock Origin. Completely removed all lag problems for me.
You can find the address of the file in the Network analysis tab of developer console (Shift+Control+E in Firefox), then just paste it to the "my filters" tab of uBlock dashboard. Hope this helps.
 "Realm Revolutions"){kind=icon}