2.5 FPS problems...

Please guys since you updated the patch 2.5 i've been having a really bad experience while playing...before 2.5 it was perfect everything was just nice until it came out i didn't know some framerate changes were happening im a windowed mode user i really hate using fullscreen it just screws everything up :S i have Geforce 970 graphic card, samsung 4k UHD monitor, 30HZ i don't know what else to mention for you guys to help on this problem...either SE updates it like it was before...or whatever...just help me please i can't play unless its on windowed mode.

Thanks in advance