Hi, i upgraded UM17.10 to UM18.04LTS and the system is using 100% CPU for any app.
Its degrade so much to use firefox, libreoffice or any normal app… its so slow. 
Intel P4 2,8MHz, 4Gb RAM.
I forgot to say that its consuming 100% CPU when its opening…
From Mate Tweak what is your Window Manager?If Compiz, can you change to Marco and test again?
Im alredy using Marco’s Window Manager…
I tried to change Marco (No compositor) for Marco (Software compositor) and solved the problem. TKS SO MUCH for the tips… 