Bob Campbell said:
Well, those are the technical, 32 bit addressable maximums. The real,
practical maximum you can actually USE is about 3.2 GB.
Yes, it is explained here:
http://support.microsoft.com/kb/929605 and here:
http://support.microsoft.com/kb/946003/ so as per SP1 Windows 32Bit can see
4GB of memory but some if it is used for other things.
The BIOS reserves memory space for video as quoted here:
For example, if you have a video card that has 256 MB of onboard memory,
that memory must be mapped within the first 4 GB of address space. If 4 GB
of system memory is already installed, part of that address space must be
reserved by the graphics memory mapping. Graphics memory mapping overwrites
a part of the system memory. These conditions reduce the total amount of
system memory that is available to the operating system.
The reduction in available system memory depends on the devices that are
installed in the computer. However, to avoid potential driver compatibility
issues, the 32-bit versions of Windows Vista limit the total available
memory to 3.12 GB. See the "More information" section for information about
potential driver compatibility issues.
If a computer has many installed devices, the available memory may be
reduced to 3 GB or less. However, the maximum memory available in 32-bit
versions of Windows Vista is typically 3.12 GB.
So, again, to use the full potential of a lot of memory you need 64Bit since
all that will be available for OS and app use is the 3.24 of 4GB in 32Bit
but most average users don't need 64Bit and it really isn't compatible in a
lot of everyday uses. A video editor can make good use of 64Bit, etc. For
games, until the future, most work better on 32Bit (for now) but eventually
64Bit may be the way to go, a more stable, compatible 64Bit OS, we might
hope.
