Hi Panais,

It's real. It was a bug in the 32 bit version of Vista where it would not always see anything over 3GB. The SP1 fixed the problem.

Shawn

Yep, it sure will.

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 functional 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 Do That Then'. So we 'Can't Do This 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.

32Bit has a TOTAL hardware memory address allocation space of 4GB when not running in PAE mode (no, don't ask...1. it won't work on "home" versions of Windows. 2. It's not a nice trade off.).

You have to allocate for devices which require address spaces based on what the ask for; USB controllers, audio cards, USB devices (external storage and the lot), and Video Cards, and THEN what is left over goes to RAM.

Vista SP1 have a "fix" that lies to you and tells you that Windows Vista Recognizes all 4GB on your system. It won't tell you how much you're actually able to address unless you look deeper under the covers (task manager and what not).

Originally Posted by panais

Emmm....
I need a simple answer for a simple question...
With sp1 installed my os and programs will benefit and use all my 4096 ram?

Thanks for ur response.

Nope.