Windows 8 Toughens Up
Despite all these protective features, malware attacks can still succeed in Windows 7. Windows 8 will block many such attacks by toughening up at the very deepest level—memory allocation. Many low-level memory functions have new safeguards in Windows 8, rejecting invalid input and adding a degree of randomness. "Guard pages" before and after in-use memory chunks prevent attacks that work by writing beyond the end of allocated memory. A new "Fast Fail" function lets a program terminate instantly if it detects memory corruption.
Source
A Guy