The story of the 3GB server switch


As Evan already mentioned on his blog, Raymond Chen has a great series on /3GB switch on his blog. What is really cool is that Raymond takes on some myths about the /3GB switch and  the fact that he makes great analogies to explain them is just a bonus. Seems like Raymond’s /3GB switch series is done now. A must read for any serious /3GB switcher – or if you ever wondered what /3GB does! =)


He discussed the following:


The oft-misunderstood /3GB switch


Kernel address space consequences of the /3GB switch


Myth: Without /3GB the total amount of memory that can be allocated across all programs is 2GB


Myth: Without /3GB a single program can’t allocate more than 2GB of virtual memory


Myth: You need /3GB if you have more than 2GB of physical memory


Myth: The /3GB switch expands the user-mode address space of all programs


Why does Exchange recommend /3GB if you have more than 1GB of physical memory?


Myth: The /3GB switch lets me map one giant 3GB block of memory


Why is the virtual address space 4GB anyway?


Myth: PAE increases the virtual address space beyond 4GB


Myth: In order to use AWE, you must enable PAE


– Nino Bilic

[You Had Me At EHLO…]

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.