Enable support for 4 gb or more ram in 32-bit

#1
So I have 6 gb ram (4 corsair 2 G.Skill) but when I go to my system properties it shows
Installed Memory: 6.00 GB (3.00 GB usable).

When I pull the 2 G.skill's out it reads:
Installed Memory: 4.00 GB (3.5 GB usable).

Two questions: why is it when I decrease my ram from 6 to 4 GB do I increase the usable amount? Also, is there a way to enable the use of 4 GB or more ram in 32-bit windows? I tried doing this using the Ultimate Windows Tweaker which was built for Vista but also works for 7, but I saw no results.
Thanks

(using build 7068 x86)
 


#2
Windows 2000 Advanced server supports 8GB RAM, Windows 2003 Data center edition supports (I think) up to 64GB RAM. These AFAIK are the only 32 bit systems that support >4GB RAM. I don't know about Windows 2008 server BTW.

If you install > 4GB RAM with "Bog standard" windows the memory > 4GB is perceived as having invalid address ranges -- the memory address / translation functions in the OS kernel therefore are using some "Error correction" pieces of code which aren't normally needed. This consumes real memory of course so less available than if this stuff isn't loaded.

If you have > 4GB memory DON'T USE a 32 BIT OS (unless you use one of the Server editions I've outlined at the top of the Post.

Cheers
jimbo
 


Kyle

New Member
#3
You can't enable more than 3.5 GB in Windows at this time.
As for why it shows more when less RAM is installed, it's likely a mapping issue.

But with 6 GB of RAM, you should be using a 64 Bit os.
 


Matt

Senior Member
#4
You can't enable more than 4GB of RAM under vista or XP 32bit: Physical Address Extension - Wikipedia, the free encyclopedia

Basically, yes, PAE can enable more than 4GB of RAM on a 32bit system (actually 36bit), as that's what OS X does, being 32bit, but it would break the drivers, so no support under the consumer versions of Windows,

So I would agree with the above, unless you plan on running server editions of Windows, go with the 64bit version of Win 7.
 


#5
Thanks for the information, good to know. I'm slightly worried about driver/software incompatibility with 64-bit, but I suppose its worth a try.
 


Matt

Senior Member
#6
So far, I've had 0 software issues, Wow64 does a really good job of running 32bit apps under a 64bit OS. As for drivers, if you have older hardware, you might have issues, as you cannot use 32bit drivers under a 64bit OS.
 


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