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Boesky

macrumors 6502
Original poster
Jul 16, 2009
364
0
I'm using the 32-bit version of it. For some reason it's telling me I only have 3.75 GB of RAM available when my MBP has 4GB.
 

Stridder44

macrumors 68040
Mar 24, 2003
3,973
198
California
I'm using the 32-bit version of it. For some reason it's telling me I only have 3.75 GB of RAM available when my MBP has 4GB.


32-bit has an addressing limit of 4 GB (that includes video card memory, which is why it drops to only 3.75 GB for you). There are some tweaks out there that change the number to show 4 GB, but that's all it does as it'll still only be able to address 4 GB.

The solution? Switch to the 64-bit version. 64-bit also has an address limit, but it's artificially set at 16.8 million terabyte. 32-bit: 4 GB. 64-bit: 16.8 TB. Yeah, insane. From Wiki:

Some operating systems reserve portions of process address space for OS use, effectively reducing the total address space available for mapping memory for user programs. For instance, Windows XP DLLs and other user mode OS components are mapped into each process's address space, leaving only 2 to 3 GB (depending on the settings) address space available. This restriction is not present in 64-bit operating systems.

Many, many people both here on this forum and in general have switch to 64-bit (for just this very reason, but there are other benefits as well) a while ago and have no issues.
 

EOC

macrumors newbie
Aug 14, 2009
16
0
I'm using the 32-bit version of it. For some reason it's telling me I only have 3.75 GB of RAM available when my MBP has 4GB.

256 MB is shared with the video card. That's why it shows up as 3.75.

My desktop has shown up as 4gb since Vista service pack 2 even though it was running 32bit vista. Of course the processor could only address 2.5GB but it would show up as 4 GB.

I'm only saying all this so that if you put 64bit on the MBP you don't get disappointed when it still says you only have 3.75 GB.
 

Stridder44

macrumors 68040
Mar 24, 2003
3,973
198
California
I'm only saying all this so that if you put 64bit on the MBP you don't get disappointed when it still says you only have 3.75 GB.


Except that it won't because he'll have a 64-bit OS, and will be able to fully utilize that entire 4 GB of RAM.
 

BeSweeet

macrumors 68000
Apr 2, 2009
1,566
1,269
San Antonio, TX
Here:
capturezv.jpg
 

mgclayton

macrumors member
Dec 19, 2007
45
0
Except that it won't because he'll have a 64-bit OS, and will be able to fully utilize that entire 4 GB of RAM.

Actually I think EOC is correct. If the NVIDIA 9400M is using 256MB of shared memory then there will only be 3.75GB available for the OS, whether it's 32-bit or 64-bit.
BeSweet's screenshot illustrates this point - 4GB installed and yet only 3.72GB available (I guess he lost an extra 0.03 somehow).

However, it should also be noted that though 32-bit Vista SP2 and Win 7 do 'correctly' show the amount installed, they can't use all of it. You're only likely to get 2.5-3.25GB in practice as the address space of the rest will be allocated to hardware. Vista used to be more 'honest' about this prior to SP2, but then people moaned as they couldn't 'see' all 4GB that they knew they'd installed and thought they'd been ripped off.
 

JessicaD

macrumors newbie
Jun 3, 2009
27
0
Boesky,

Windows 7 32 Bit can only recognize up to 3.5 GB of RAM. If you plan on using what your MBP actually has installed you would want to install Windows 7 64 Bit.

Also, Microsoft does have an official Windows 7 RC Support Forum located here http://tinyurl.com/9fhdl5 . It is supported by product specialists as well as engineers and support teams. You may want to check the threads available there for additional assistance and feedback.

Jessica
Microsoft Windows Client Team
 

Stridder44

macrumors 68040
Mar 24, 2003
3,973
198
California
Actually I think EOC is correct. If the NVIDIA 9400M is using 256MB of shared memory then there will only be 3.75GB available for the OS, whether it's 32-bit or 64-bit.


I'm retarded, I misread his original post. Yes, shared VRAM means it will take from the actual RAM, which is why 3.75 GB is available instead of the full 4.
 
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