Ya its not that Zero page. This is just a page of zeros. When you allocate virtual memory the OS gives you the virtual allocation but the physical allocation points to the page of zeros. So when you read you get zeros. Only when you write does the OS allocate a real physical page of memory (which is should zero before handing over to the application). The reason why is important for the random read test is that if he does not initialize memory he might not be reading from dram but constantly reading the zero page which would be very fast.

Awesome, just wanted to check.

I'd very much enjoy reading a blog post about your findings, if you are interested in writing one. Thanks for sharing, modern CPUs really are quite incredible.