Windows Vista – Dynamic Address Space

System virtual address (VA) space allocated on-demand 

Instead of at boot time based registry & configuration information

Region sizes bounded only by VA limitations 

Applies to non-paged, paged, session space, mapped views, etc.

Kernel page tables allocated on demand

No longer preallocated at system boot, saves 

1.5MB on x86 systems3MB on PAE systems

16MB to 2.5GB on 64-bit machines 

Boot with very large registries on 32-bit machines

With and without /3GB switch Important for large multipath LUN machines

MM locates registry VA space used by boot loader & reuses it as dynamic kernel virtual address space 

Key Benefits of Dynamic Address Space

NNo registry editing & reboots to reconfigure systems due to resource imbalances  
Maximum resources available in wide range of scenarios, w/ no human intervention
Desktop heap exhaustion
Terminal Server maximum scaling
Large video clients
/3GB SQL and Exchange machines
Http servers, NFS servers, etc
Features enabled w/o reboot, yet have no cost if not used
64-bit systems grow to maximum limit regardless of underlying physical configuration
128GB paged pool, nonpaged pool
1TB system cache/system PTEs/special pool
128GB session pool
128GB session views (desktop heaps), etc