What is the difference between the Intel x86 Atom and Atom_64 system images?

Question

I am using the Android SDK Manager to install the system image for the Android M Preview. However, I noticed that there are two separate images for the x86 platform.

Answer 1

x86 means 32 bit system. Now I have read all the above answers and I'll directly come to the point.

x86 Atom -> 32bit Intel CPU with 32bit android simulation

x86 Atom_64 -> 32bit Intel CPU with 64bit android simulation