Linked by Thom Holwerda on Wed 5th Jan 2011 22:09 UTC
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It also shows that MS' implementation of AWE requires physical pages and is therefore unsuitable to extend addressing. On client systems it's only useful to get from 2Gb to (some value less than) 4Gb.
I'm sorry, I think we were talking past one another - I thought you meant that client versions of 32bit Windows had zero options to go past the 2GB limit for applications. We actually meant the same thing, except I was unaware of the 4GB limit of AWE. Thanks for clarifying!




Member since:
2005-12-04
This is simply wrong.
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Have you looked at my Bio? I work on Windows full time. If you want me to go over memory management, I can bore you to tears, but it's very unlikely that you'll be able to dismiss me that easily.
Firstly, here's the page that describes limits on physical addressing:
http://msdn.microsoft.com/en-us/library/aa366778(v=VS.85).aspx#physical_memory_limits_windows_7
Second, this section might be helpful (the part that talks about how PAE, /3Gb, and AWE are related and not related):
http://msdn.microsoft.com/en-us/library/aa366796(v=VS.85).aspx
That's all well and good, but it's still subject to the physical memory limits described in the link I gave above. See the part where it says "The physical pages that can be allocated for an AWE region are limited by the number of physical pages present in the machine, since this memory is never paged..." What this link really shows is that a single process, which has 2Gb of VA, can use greater than 2Gb of physical pages on a 32-bit client system. It cannot use more than 4Gb of physical pages, since that's the absolute maximum the client system will ever use.
It also shows that MS' implementation of AWE requires physical pages and is therefore unsuitable to extend addressing. On client systems it's only useful to get from 2Gb to (some value less than) 4Gb.