Re: Use 3GB or 4GB RAM in 32 bit OS?

phil-news-nospam@[EMAIL PROTECTED]
 wrote:
> The displaced RAM gets mapped above the 4GB line.  A kernel with PAE
mode
> can access all of up to 64GB (and possibly 128GB with a hack).  So if
you
> have a baord that can do 64GB and you put 64GB in it, you will then be
> back to the problem of losing a sub-GB chunk of memory.  People will be
> whining about this problem a lot in a few years :-)
> 
> See also:
> http://en.wikipedia.org/wiki/Physical_Address_Extension


If you have a newer processor with the hardware Data Execute Prevention 
(DEP, aka No Execute bit, NX-bit) feature, Windows automatically puts 
you into PAE mode, even if you don't have more than 4GB installed on the 
system. That's because AMD (who created the mechanism, followed by 
Intel) decided that only the newer PAE-style page tables and newer 
should have this feature implemented in them.

But even though PAE is enabled, 32-bit Windows still doesn't remap the 
missing ram between 3-4GB. I guess it just finds it not worth the 
effort. 64-bit Windows will remap it and use it though.

	Yousuf Khan