FPS (slideshow) problem

Hello,
last times playing GW i have sudden FPS spikes. Usually having 50fps comes to 2-9fps for no reason and last for like 20-30 seconds after it comes to normal. It is not deffinitely caused by anything ingame, like bigger groups of mobs or players, because it happens when i m standing in empty Gh as well.

If any1 know what the reason of this could be, I d really appreciate help or suggestions.

Thanks in advance

I've been getting lag spikes, you may be having the same problem