I do not speak very much Portuguese but I think I understood your question.
The configuration you have is indeed very good so I would say that if the system is very slow there may be something on the Operating System that is causing this problem.
Try running the Antivirus on the system in case there is malware affecting the performance. In the worse case, reinstalling the Operating System will do the trick.
I am sorry to write it in English but you can use the translator tool here or google translate tool as well.