add more ram
You can download a modification called Optifine. Optifine is a mod that smoothens Minecraft performance. Doubling FPS is very common with this modification but that really depends on computer specs.
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...
Turn every graphic quality to low and make sure all programs using RAM are closed.
Turn the graphix down or get a better computer.
/toggledownfall to stop or make rain in minecraft
Try servers that aren't as busy. Or try a different computer if possible.
you might have to make the graphic quality lower. check if you computer meets the syste requirements, because if it doesn't then it can cause some serious lag.
If it lags to much, you need to download the newest version of Java Runtime Environment, then set it back to far. It should stop lagging
Usually you would clean out unessary files, and programs which would make it alot faster. It may seem like it won't work but trust me it does. Hope this helps :)
Your problem is in your question. With the router hooked up to the computer its using the Internet from the router which is probably what your son is using as his Internet source causing him to lag. Just make a schedule. Time him then have your time on your computer then when your done he can get back on his Xbox.
go to video settings turn smooth lighting off and turn your graphics from fancy to fast. you turn smooth lighting off and i best recommend you download 64 - bit java Sweet! I've just received my free minecraft giftcode! >> Minecraftcodes.info <<
Compare the specifications needed to run DC Universe Online at an acceptable level with the specification of your computer. I'm willing to bet you have a very old computer, that simply is not good enough.