Massive FPS drop after Alt-Tabbing

Hey, i got problem with my l2 client last days (since i downlowaded game to play on ramona). I never had same problems like this with any game (L2 europe included). The problem is when im doing Alt-Tab and maximize my game after i got massive fps drop. Literally cant do anything.
Only solution for this is maximize my window to full screen and then again make it in window mode (double Alt+Enter), after game works good. But its kinda annoying wasting time for maximizing my window.

Tried several things to fix it out but nothing work from reinstalling drivers, installing older versions, reinstalling game, cleaning registry etc, running game on low details, PC temp is fine etc...

Hope you will be able to help me solve this problem because im not able to launch another game window to play normally.


Radeon HD 7700
intel i3-2120
ssd
4gb ram

 

Maybe u using w10 and u forget closed xbox ? options u need turn off

 

Sorry forgot to say that im using win7 x64