[GAMEPLAY] Recently update make borderless and windowed mode SO lag

After May 2 or 3 update, the league borderless and windowed mode make me so LAG (normally I have 130FPS, but now I only have 30~40, and yes my ping is stably 62) I even update my graph card (NVIDIA GTX 760M) driver to see if it is the problem or not but it didn't work, so I lower my driver but it still didn't work I've tried to lower the setting quality , but FPS didin't change at all I also reinstalled it 2 times in different hard drive but nothing change

Just 30 min ago, becasue I reinstalled it so it change to defalut setting which is full screen instead of my usual setting boarderless, and my FPS finally come back, so I think recently updates cause these problems (not the 5/4 update, becasue I have these troubles before that day)