Sign in with
Sign up | Sign in
Your question
Closed

Maximum ram for Win 7 32-bit?

Last response: in Memory
Share
January 11, 2011 12:03:09 AM

I have a Dell Dimension E520 with Win 7 32-bit, with 1 GB of ram.
Lets say I put 3 more gigs of ram to the system, totaling 4GB.

What would be the max usable RAM? I have read that some systems go between 3 and 3.5 GB usage, and the manual does not mention Win 7 because its Vista Certified, so i can't really tell how much would be the limit.

Extra Credit: What if you had a graphics card with 512 MB of video memory? Does this add up to the Limit, making the extra gig useless?

More about : maximum ram win bit

Best solution

a b } Memory
January 11, 2011 12:38:17 PM

In a computer all bytes in the memory system need a unique name. This is called an address. For example, if you have 2 GB of main memory, then there are 2147483648 bytes of RAM in your machine, each of which require an address for the operating system to communicate to it. To give these all an address you need 31 bits to do it. Now, if/when you have 32 bits, you can name 4 GB (2 bytes to the 32nd power = 4GB).

This is why the total addressable space available in a 32 bit OS is 4GB – the OS runs out of addresses and cannot communicate/locate any more bytes of memory because of that.

You may think ”Hey, 4GB of address space… 4GB of RAM… What’s the problem” The problem is that memory isn’t the only thing needing an address. 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 functional computer. Therefore the OS designers assign RAM last.


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: Windows Vista 32bit SP1 and newer versions will display the installed amount of RAM, regardless of how much is accessible. This is a display change only.



Regarding your Video card: Not everything is memory mapped - typically 256MB for the aperature.
Share
a c 347 } Memory
January 11, 2011 1:58:04 PM

Best 'guessing' 3.0GB~3.3GB usable MAX with 0.5GB going to the GPU. The highest I've seen w/o an onboard GPU is 3.8GB usable hence the range.

Your MOBO supports max 2GB per DIMM X 4 = 8GB and obviously you'll need an x64 OS, and even then the MAX usable will be ~7.5GB {less the 0.5GB on board GPU}. If you have a discrete GPU you can either disabled {Disable} the onboard or reduce it to the lowest 'shared' value per BIOS.
Score
0
Related resources
January 11, 2011 7:59:35 PM

Best answer selected by Atomzdan.
Score
0
a b } Memory
January 12, 2011 6:02:56 AM

This topic has been closed by Maziar
Score
0
!