I have tested Ubuntu in i7, i5 but lower then 4 core/8 thread CPU. In two system which has i7 processor with 4 core/8 thread i have the same problem. After reboot it never reboot itself auto.
I need to physically turn it off (power out), and power on.
What is the way to reboot for such system? (less then 4 core/8 thread CPU its working nicely).