As the title says, I have a serious problem with my main client. It lags, it won't run in 60 or even 30fps. Animations aren't smooth etc. PBE client, on the other hand, is perfect. Nothing lags, it responds immediately, runs at stable framerate, and sounds don't stutter.
I tried using your Hextech Repair Tool, reinstalling the client (with clearing everything that remained of it deep in the libraries using some programs recommended by Support when I had other issue with it), running it with either integrated GPU or normal graphics card but this EUNE client is still garbage. (And it's been like that since the new client was implemented).
GeForce GT 755M
But I don't think those matter since the PBE works just fine. I can record it if you want to see what I have to deal with. If only I could just use the PBE client as my regular one...