Chat with our AI personalities
You cannot stop it however you change the settings, eg fancy to fast and/or your render distance, so that your computer has less to think about and so runs it without as much lag.
Depends on how much RAM you have if you have a good amount 6 gigabytes or more is pretty good for minecraft than you can search how to dedicate ram to minecraft. Or just watch this video...
/toggledownfall to stop or make rain in minecraft
To get DeSmuME to stop lagging, go to Configuration, then Frameskip. Set the frameskip to 9, and limit the frame rate. That should get DeSmuME to a speed where it almost never lags, and never goes too fast.
Get a job and buy a better internet router.
1. Your computer doesn't have enough ram. 2. There is too many people on your server. OR 3. Your server doesn't have enough ram. :)