FPS DROP WITH 5.4 PATCH OR IS IT THE DJ SONA SKIN???

OK, ever since the release of patch 5.4 I have been having extremely erratic behavior with my FPS. Before the patch my FPS was a constant 60 FPS, but since the batch it will drop to 30 and fluctuate all over the place never staying at any one place. I did buy the new DJ Sona skin, but when I turned all my graphic settings down to low it actually got worse.

I wanna know if this is an unexpected bug from the patch or what? and what Riot plans to do about it thank you.