Hi bhanusanam,
Your i7 processor has 4 real cores, virtualization splits each core into 2 threads, giving a total of 8 threads on your processor - right click the graph in your screenshot and choose 'Change Graph to' - 'Logical Processors' to see that in action
That is managed by the processor firmware and Intel software. Honestly it is est to leave that setting to to software
If you do want to turn that off, (though it would serve no purpose), go into your BIOS you will find the virtualization setting there