When installing Windows Vista SP1 for your 32-bit operating system you may be fooled into believing that you do in fact have more than 3GB of memory and that the operating system is taking advantage of that. In pre SP1 installs only 3GB will be detected and reported. After installing SP1, since I have a compatible BIOS, Vista recognizes the fact that I have 4GB of memory installed on my motherboard. However, as far as I understand, it won’t actually use it. Here’s a quote from the Notable Changes in Vista SP1 document:
With SP1, Windows Vista will report the amount of system memory installed rather than report the amount of system memory available to the OS. Therefore 32-bit systems equipped with 4GB of RAM will report all 4GB in many places throughout the OS, such as the System Control Panel. However, this behavior is dependent on having a compatible BIOS, so not all users may notice this change.
And here is a more detailed explanation as to why there is a 3GB limit in 32-bit operating systems, regardless of it being Vista SP1 or anything else.
Although my computer is what passes for a high performance model it came pre-installed with a 32-bit operating system. Since the processor it features is an Intel Core 2 Duo processor, that’s 64-bit capable, I’m considering re-installing. I just have to read up on the impact of having a 64-bit operating system, how it impacts my applications, battery lifetime etc. Anyone want to share their experiences running 64-bit compared to 32-bit or have a link to some good up to date resource that talks about it?