Too many chests within a player's render distance significantly reduce their FPS.
This can be tested by filling (/fill) a chunk with chests and facing that chunk (so its in your field of view).
In comparison, a chunk full of barrels or hoppers do not cause any FPS drop at all. This FPS drop can be noticed only with chests and ender chests.
Related issues
Comments
[Mod] OcelotOnesie
migrated
Thank you for your report!
We're tracking this issue in MCPE-137537, so this ticket is being resolved and linked as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki