Lowering the priority does nothing for me.
CPU usage capped at 99% when the launcher/client are running. When they're not, my framerate returns to normal. But I'm sick of closing LolClient.exe every time I want to play the game, because that's stupidly counterintuitive. All of my drivers are up to date, so that's definitely not the problem. I have no trouble running any other games--other games which use WAY MORE processing/graphics power. This is definitely a problem with the AIR client, which is bloated, awful ****.
I almost feel like this started when you guys upgraded to AIR 2.0.
Logs were submitted in-game through the help ticket menu, but if you'd like me to post them here too, I will. I'm wondering if you guys are doing anything about this, considering we keep seeing "post your logs" and "is this actually happening? I've never seen it" as responses, I'm inclined to think maybe you guys aren't actually addressing the FPS issues.