how come when ever thresh dies my FPS drops? even my friends said that they lag

bump

When you lag is it for like 5 seconds? Is this only when playing against/with thresh or is this wide spread since the patch?

If you are seeing a FPS, I would try to repair your installation, open the launcher and click the cog wheel in the upper right. This process can take some time, but it should resolve the problem.

The issue can be caused if there are corrupted files that relate to him, animation files and such.