Ubuntu 19.10 beta version run quite smoothly, better than previous ones IMO. As it's been officially released, I just want to make a clean installation and then the problem occurs. it stucks randomly either before installing guide or partitioning section or so. one time the monitor turned to be dark screen messaging out of memory blah blah, which reminded me of extending the RAM size. so I tested the iso on virtualbox with 2GB memory, it got stuck just like my physical pc, then I adjusted it to 3GB. the OS was installed successfully. So I think maybe the iso needs to be modified or the system requirments got to be improved on official website.