Nah, i think you have another issue
First of all
Close all lmms-sub-windows so only the bare main-component is open.
What cpu-usage does you have then.
If it still overshoot, i like to have the project
upload the project, AS MMP! -and send me the link as PM (just right-click my name in byline and choose Contact musikBear), i will take a look at it
To Save as MMP:
* Open project
* File | save-as
* chose a name... 'xyzzxy.mmp'
press save
You can upload on any file-host like google drive
I will ofcause respect your rights