Does this bug still happen to you? Could you please provide some of these details:
- How much RAM do you have? Is it running low when Opera slows down?
- Do you use an antivirus software? If yes, which one?
- Is this a laptop computer? What kind of graphic card it uses? Which version of drivers?
- Was your internet connection stable when the bug occured?
- Is this still happening in the newer versions of Opera?