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The bug tracker is not a help site, so I would recommend visiting the Community Support Discord server for help.

Thank you for your report!
However, this issue is Invalid.

Performance drops are expected to happen between versions, especially in betas. Simply stating that "My game is laggier" is not helpful for Mojang to diagnose your issue. If you can pinpoint a specific cause when lag happens for you, please open a new report for that specific issue. If you think this might be a hardware issue please contact Community Support as they might be able to help with your issue.

Keep in mind that Mojang is constantly optimizing the game and simply playing the game provides feedback to Mojang on which parts cause performance issues.

Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki