Win Vista 32bit supports 4GB ram???

i read in some post that winxp 32bit does not support more than 3GB ram, that only the 64bit version... my question is win vista 32bit has the same limitations or they fixed that in this generation of windows??

 

It's a complicated question with a complicated answer but the short version is that Vista has exactly the same limitations unless you get 64 bit Vista.

 

dont understand this limitation... the only reason i see is to make people to move on to the 64bit version in a few years

 

Any 32 bit OS can't address more than 3.2 GB of RAM.. It won't "see" all of it...

 

A 32bit OS can address exactly 4GB of memory...but, some of that 4GB space is stolen for the system to use (aka: some of that address space is used for USB ports, CPU parts, other ports, PCIe lanes, etc, etc). Most 32bit systems, after addressing all the PC parts, have about 3.2-3.5GB left of addressing space and that is why only 3.2-3.5 of RAM can be found by the OS.

 

Found the following explanation online:


Due to an architectural decision made long ago, if you have 4GB of physical RAM installed, Windows is only able to report a portion of the physical 4GB of RAM (ranges from ~2.75GB to 3.5GB depending on the devices installed, motherboard's chipset & BIOS).

This behavior is due to "memory mapped IO reservations". Those reservations overlay the physical address space and mask out those physical addresses so that they cannot be used for working memory. This is independent of the OS running on the machine.

Significant chunks of address space below 4GB (the highest address accessible via 32-bit) get reserved for use by system hardware:

• BIOS – including ACPI and legacy video support

• PCI bus including bridges etc.

• PCI Express support will reserve at least 256MB, up to 768MB depending on graphics card installed memory

What this means is a typical system may see between ~256MB and 1GB of address space below 4GB reserved for hardware use that the OS cannot access. Intel chipset specs are pretty good at explaining what address ranges gets reserved by default and in some cases call out that 1.5GB is always reserved and thus inaccessible to Windows.


Apple was smart and went to 64-bit support much earlier.

 

It has nothing to do with marketing and EVERYTHING to do with binary. Two to the 32nd power is 4,294,967,296 or 4 gig. If you only have 32 bits to generate an address (aka a 32 bit operating system) you can only address 4 gig of memory. But then I suppose we could go back to the old 8086 days of paged memory and address more. <grin>

Gary

 

You have have 4GB of memory in total. RAM, and VIDEO MEMORY. I have 4GB installed, but I also have dual 8800gtx, which are 728mb each, so Vista sees 2.5GB of RAM, and 1.5GB of video memory, so thats 4GB in total.

if you have a 64mb video card you should have around 3.9GB of ram.

 

All of what is said is true. In 0x86 systems there is one address space for memory, motherboard BIOS and other device BIOS, video ram, system ram (your ram modules), and other memory gets mapped into the address space. There is one "address bus" which the CPU address its data on so things get mapped and share the address space.

But not all OS will map 3.2GB out of 4GB of ram, depends on how much memory the OS needs to reserve for itself for protection purposes and what devices are installed.