Do you mean true fps or server lag?
If I remember good, there is option in settings to see your current fps.
You may try to update/downgrade/reinstall drivers (yes, mentioned many times, but this is popular source for performance drop in specific versions), change DirectX in settings, switch between 32/64 bit client.
I did not notice any difference on Ghallanda since last update, so this might be server, time zone or hardware individual (yes, I am familiar with differences between uncomfortable 30 and smooth 60 in games).