This is what I think:
Linux is based for security. They are developping the OS for the best security.
Microsoft is not based for security. they develop their Os then put something called a patch of security.
It's like the intel. Their EM64T CPUs are actual 32-bit CPU that they put a "layer" of a 64-bit. the AMD Athlon 64 bulds are made of 100% 64-bit CPU and 32-bit compatible