Q. I installed 4GB of memory into my Windows Vista 32-bit installation. Why am I seeing only 3GB?
A. I recently added 2GB of memory to my main workstation and after turning on the machine, the startup showed that the BIOS saw 4GB yet Vista saw only 3GB. Essentially it's because 32-bit Vista can only address 4GB of memory space but if you have other devices that have memory, such as a 660MB graphics card, they take away from memory that the OS can use. When I upgrade to 64-bit Vista, I saw all 4GB of my memory.