Yes its like a keyboard lag! not on desktop , but laptop I've gone back to Avira free fresh install, and I'm using their chat on a new tab seems ok. Rather than that tiny chat box, any other ideas i did run the C/ Clean up utility also.
The only thing I can suggest is a clean install of Windows. I've only seen the keyboard issue on one computer. A clean install of Windows would have fixed it, but that is something I do not want to do.
It's possible the keyboard lag is caused by an addon. Have you tried starting the browser with addons disabled? Do you have an antikeylogger installed? Some AV hook too deep into the browser that cause crashes and slow down. Why not use MSE or WD?