Memory >3.5GB not used?

Ivan Voras ivoras at
Wed Apr 25 08:02:50 UTC 2007

Bill Moran wrote:

 > Does this test demonstrate usage of memory over 4G?  It's my 
 > that PAE starts to suffer when it has to look at the memory over 4G 
 > is the problem it's intended to solve)
 > If your entire test fits in under 4G, you're not seeing the worst of it.
 > At least, that's my understanding of the issue.

I don't think that's how PAE works. AFAIK, it adds all the memory pages 
it can find (including those above and below 4 GB) into the VM pool with 
64-bit addresses, so all of them can be used by the applications in an 
uniform way. Kind of like swap works.

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