All of a sudden, after a couple of years of use, Opera has started hogging CPU for no apparent reason. In the task manager, no tab is misbehaving, 3% is the highest one, but the browser CPU remains over 100% consistently, as soon as I start it up. I have disabled all extensions, toggled hardware acceleration and tried other fixes I found here, but they don't work for me. Any ideas? This renders the browser unusable.