[-Sevendust-]

I have 4 gigs of ram installed but it only shows 3. Im reading that people have it showing 3.5. How do I get it to do this?

Had to dump my vista install because everytime I downloaded a file it was corrupt.

[Juballharshaw]

Regular XP is a 32 bit operating system that doesn't have the capacity to address RAM beyond that 3.5 gb range. You'll need a 64 bit OS like Vista, XP-64, OS-X or the various Linux distros that support 64 bit.

[j0k3r]

You can't, it's a hardware limitation. And the more devices you have in the machine, the less you will see. Memory gets reserved for hardware memory mapping. It's still getting used, it's just not all available to the operating system.

[-Sevendust-]

ok, i should of put I knew all of that.

But why do some people see 3.5 that are running a 32 bit os and Im only seeing 3.

[Juballharshaw]

Why does a 32bit Operating System address 3GB of RAM and not 4GB?
The best answer yet is;

The PCI memory addresses starting down from 4 GB are used for things like the BIOS, IO cards, networking, PCI hubs, bus bridges, PCI-Express, and video/graphics cards. The BIOS takes up about 512 KB starting from the very top address. Then each of the other items mentioned are allocated address ranges below the BIOS range. The largest block of addresses is allocated for today’s high performance graphics cards which need addresses for at least the amount of memory on the graphics card. The net result is that a high performance x86-based computer may allocate 512 MB to more than 1 GB for the PCI memory address range before any RAM (physical user memory) addresses are allocated.
What this means, using 32bit XP or Vista there is a theshold of 3GB RAM - any graphics cards for example a 256MB graphics card will use 256MB of that reserved 1GB upper memory that XP/Vista is unable to access for that. So your computer will only see 3.25GB of RAM, for example if you have 32-bit OS & 256MB graphics card.

And as far as a 32-bit Vista and Windows XP are concerned the entire world stops at 4GB RAM. There is no way you can access more than that.

232 = 4,294,967,296
4,294,967,296 / (1,024 x 1,024) = 4,096 (4GB)
Now don't be confused about your 64-bit hardware, this changes nothing. Your 64-bit system which is running a 32-bit OS, still runs in 32-bit mode. As a 32-bit Operating System is unable to access the full 64-bit capability of the hardware.

[j0k3r]

Originally Posted by j0k3r

You can't, it's a hardware limitation. And the more devices you have in the machine, the less you will see. Memory gets reserved for hardware memory mapping. It's still getting used, it's just not all available to the operating system.

Originally Posted by -Sevendust-

ok, i should of put I knew all of that.

But why do some people see 3.5 that are running a 32 bit os and Im only seeing 3.

[-Sevendust-]

Guess I looked over your post. Sorry.

[ShabazKillaX]

Edit the boot.ini file and add /PAE to enable physical address extension.

Operating Systems and PAE Support

[-Sevendust-]

nm

[Miller]

xp 64bit