Computer seems to detect only 3GB of ram

[MattTheTubaGuy]

My computer, (os Windows Vista premium), seems to only detect 3GB of RAM for some reason. In Task manager, it shows the total memory as 3069MB, even though the Setup Utility shows that I have 4096MB.
Also using Autodesk Inventor, it crashed when there was still more than 1/2 a GB of ram left because it ran out of memory, which seems strange.
Is there a way of fixing this problem?

 

[snowchick7669]

Here's something you may find interesting and explain as to why it is only addressing the 3GBs of RAM.

Basically you need a 64bit operating system to recognise more then 3-4Gbs of RAM. The link above will explain the differences between both types of OS

One of the greatest advantages of using a 64-bit version of Windows Vista is the ability to access physical memory (RAM) that is above the 4-gigabyte (GB) range. This physical memory is not addressable by 32-bit versions of Windows Vista.

 

[Tedster]

32bit operating systems can only address around 3GB of RAM. To use more you will need a 64bit OS.

 

[T77]

Yeah u need a 64bit os,theres no point of having more than 3gb of ram when u r using a 32bit os

 

[red1776]

Hey Matt,
the short version is that it is something called MMOI, memory mapped I/O reservations, its an architectural design and decision made long ago when the idea of having a full gig of ram was thought to be preposterous and would not ever happen or be needed. in a 32 bit os it lets you use somewhere between 2.75 and 3.25 Gb of 'working memory' and reserves the rest for things like pci buses, installed hardware, etc. the other Gig is there, you just don't get to use it as working memory. hope that wasn't to much babbling

 

[Justin]

The posters above have mostly covered it, but another point to bring up is the Kernel/Application memory split. On 32-bit editions of Windows XP/Vista, there's an upper memory limit of 2GB that programs can actually take advantage of. Without modifying your OS, you will get severely diminishing returns on memory sizes >2GB as the Windows kernel will reserve that extra memory solely for itself/Windows executive processes.


You can read more here: http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx


So really to take advantage of 4GB of memory, you'll need to switch to a 64-bit version of Windows.

 

[red1776]

great point Justin,
there is a program, software, that will let a program (say photoshop,etc) access more than the two gigs.

 

[captaincranky]

Just so we're clear, M$ indicates that the "3GB switch" can only be applied to XP >Pro< and server editions.

Are they lying? Dunno.

 

[red1776]

Im not sure, i never used it but i have heard others claim that they have done it with XP as well.