Black Screen -> Low FPS problem

[sasakusaku]

This is strange problem that occurs occasionally for me, often times many times in a row if I am in same area.

Using 660 Gforce ti/i7/8 gig ram/win 7/not sure drivers (they are a few months old)

This does not happen in any other game I play so not sure if it's a system problem or a game bug. Wondering if anyone else has encountered this...

What happens is: the game will freeze, then the screen will go totally black for 5-10 seconds, and then the game will pop back up but at severly reduced FPS (5-13) which is unplayable.

While the screen is black; the cursor is still up and the game is apparently still running. I can still play but the FPS is dreadfully bad...

To fix this, I have to restart client from scratch. This problem usually repeats a over and over within 1-10 mins until I move to a new zone which tends to make it stop. Weird thing is that I have played for upwards of 12 hours straight with absolutely no problems then it happens. I am not sure what triggers this. So far it only happens in open world, however I have not done that many instances yet. Have tried many different settings but to no avail.

It might be something to do with the time of day in game and or perhaps when I right click/hold to pan over hidden UI bars. I am using 2 verticals and 2 horizontals. The horizontals might be the problem? Might be something to do with a player/npc skill graphic since I am usually in combat when it starts to bad. I can't seem to reproduce it on demand.