Period Graphic Issues

First time posting on the forums, so be gentle, please!

I'm experience severe FPS drops at random places, sometimes near other players, sometimes not, usually the game runs at around 60 FPS, at which i have it capped, but it would drop down to about 10-15 for a period of 25-30 seconds, then restore itself, or other times until i leave the zone it stays there.

A moment ago i was doing a fate and my FPS was fine, suddenly my windows theme changed to basic and despite the FPS issue remaining there, until all players left my screen, it would not go back to normal. I have disabled windows changing themes for me a while ago and it hasn't done much, i have also updated my graphic drivers today, and it has not resolved the issue. The PC is not overheating, having checked with GPU/CPU-z and Everest, the machine itself is cool and while the game is experiencing these issues, my computer does not crash, i get no freezes, and my processor/memory remain at the same levels, meaning the usage does not show as if its capped. I have done absolutely no clocking on it.

PC specs:

GTX660 2048mb(Bit rate of 296, last i checked?)
FX-6300, six core, 3.5ghz, 14mb cache
8GB of RAM, DDR3-1600
Game is installed on a SSD along with my windows 7, 64xbit

As mentioned, i've disabled windows swapping my themes, I've upgraded the drivers and have tried the various guides about in game settings. The problem is that the FPS Is inconsistent. Any advice, ideas and suggestions are welcome, would love to hear anyone that managed to make it work using similar specs. If you require any information of me, please state how i should acquire it to prevent confusing and a slow response, thank you in advance!

I played last week and had great FPS in the cities. Logged in today and everything moves real slow. Takes some time for a window to fade in. And it can't be the number of players around me, that hasn't changed. What did SE do in maintenance that messed it up so bad?

This has been happening since i bought the game! So for me its not related to the patch or maintenance, just to add!

Bump, still could use some advice, i meant periodic* graphical issues!