In order for us to provide better support, we need to see the log generated by Citra. This guide will walk you through how you can obtain the log file: How to Upload the Log File.
Include your system specs, cpu, gpu and log. you can try canary-1041 which was the last build with the ‘Ignore format reinterpretation hack’ which can prevent lag on certain circumstances (just keep in mind that old builds aren’t recommended).