Android tablet very laggy and freezing for 3 minutes (slow internal storage?)

I have Pipo M9 Pro with Android 4.2.2 OS is quite laggy and to use Chrome is almost impossible... it is so very slow and sometimes I cannot do anything for 3-5 min because of freezing. I made some tests with AndroBench and it looks like the internal storate is very slow. Could this be the main and only problem? Also for the freezes? Should I just get a fast SD card and link everything to there? With which app? How can I then take the card out and copy something to it?