short on RAM

[Seifer]

A buddy of mine got this mobo http://www.newegg.com/product/product.aspx?Item=N82E16813141005 and this RAM http://www.newegg.com/product/product.aspx?Item=N82E16820145176 today and we put it all together with Windows XP... Well the problem is the my computer properties says it only has 2.75GB is in there, when in fact we installed 4gb. Now I know you will not get the 4gb total without OCing but why is there that much difference?

4gb->2.75gb...

 

[jkflipflop98]

Just out of curiosity, why do you think overclocking will give you more usable ram?

 

[baracuda73]

Overclocking has nothing to do with it. 32-bit windows and only address 3gb of ram in Xp and to address the rest you will need to install 64 bit xp or 64 bit vista.

 

[systemlord]

Overclocking has nothing to do with it. 32-bit windows and only address 3gb of ram in Xp and to address the rest you will need to install 64 bit xp or 64 bit vista.

baracuda73 is right, 32bit OS's can't address more than 3.25GB of RAM. Try enabling [Memory Remapping] in BIOS.

 

[antas]

Indeed

Below are some urls for your reference:

Anand: http://www.anandtech.com/gadgets/showdoc.aspx?i=3034
Toms: http://www.tomshardware.com/2008/02/15/vista_workshop/page3.html
Other threads: http://www.tomshardware.co.uk/forum/forum2.php?config=tomshardwareuk.inc&cat=12&post=248214&page=1&p=1&sondage=0&owntopic=1&trash=&trash_post=&print=0&numreponse=0&quote_only=0&new=0&nojs=0#t1760233

 

[nukemaster]

i beg to differ on the 3.25 max

The numbers do not add up tho...that was only a 4megabyte pci video card(S3 FTW)...they do add up with a 8800GTX @ 3.25....

2.75 looks almost like a sli/crossfire setup

 

[Scotteq]

In 32 bit Windows operating systems, the total addressable space available is 4GB. If you install a total of 4GB worth of RAM, the system will detect/use/display less than 4GB of total memory because of address space allocation for other critical functions, such as:

- System BIOS (including motherboard, add-on cards, etc..)
- Motherboards resources
- Memory mapped I/O
- Configuration for AGP/PCI-Ex/PCI
- Other memory allocations for PCI devices

Different onboard devices and different add-on cards (devices) will result of different total memory size. e.g. more PCI cards installed will require more memory resources, resulting of less memory free for other uses.

This limitation applies to most chipsets & Windows XP/Vista 32-bit version operating systems. Again, this is a limitation of the Operating System not having enough address space to allocate to the system *and* the RAM. Not allocating address space to devices renders them inoperable. Not allocating addresses to RAM simply results in the unaddressed section not being used in an otherwise fully functionsl computer. Therefore the OS designers assign RAM last.

We can have long debates about mathematical fundamentals and discussions about why the original Windows designers couldn't allocate the full theoretical max of 36 bits of address space so that users today would be able to use more resource. But at the end of the day, the designers and engineers 'Didn't Then'. So we 'Can't Now'.


If you install a Windows operating system, and if more than 3GB memory is required for your system, then the below conditions must be met:

1. A memory controller which supports memory swap functionality is used. The latest chipsets like Intel 975X, 955X, Nvidia NF4 SLI Intel Edition, Nvidia NF4 SLI X16, AMD K8 and newer architectures can support the memory swap function.

2. Installation of Windows XP Pro X64 Ed. (64-bit), Windows Vista 64, or other OS which can provide more than 4GB worth of address space.



Note: According to the latest Change Log published by Microsoft, Windows Vista 32bit SP1 will display the installed amount of RAM. This is a display change only.