This is yet another Render Dragon bug. There is a chance when you open the game, the game will lag spike each second, I never came across this until Render Dragon existed. Two pictures because I reset Minecraft or I just opened another application that needed admin priv.
Thank you for your report!
However, this issue is Invalid.
Simply stating that "My game has random lag" 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.
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