*   ",,,the amount being reported by Windows isn't a problem."

*It's not a problem so long as you don't mind paying for RAM you can't use. When Windows reports 3.5GB, that's all it can see and use.

The real 4GB limit in 32bit operating systems isn't physical RAM; it's memory address space. Physical RAM has to access address space, as do other hardware items such as graphics cards. Most other hardware devices are designed to read and write via the upper 1GB of address space, with most of the lower 3GB being available to physical RAM. Since Windows would fall over if it couldn't access those other hardware devices, it always gives priority to those. RAM gets what's left over.

When you have 3GB of physical RAM or less, you don't (normally) lose any of it because the other hardware is assigned to the memory address space in the region above. Once you go above 3GB of RAM, it's down to the configuration of your other hardware as to how much you get. The maximum reported RAM I've seen mentioned on the web is 3.63GB, but this was on a bare system with a puny graphics card. If there's lots of other hefty hardware, it can actually take address space below 3GB.

The other kicker is the way Windows divides the address space between its own kernel (along with drivers, etc) and applications. By default, the max available to applications is 2GB of address space. Obviously if you only have 2GB of physical RAM, then Windows has to pinch a load of potential app address space for itself. If you have 3GB of physical RAM, then the apps get their full 2GB and Windows gets 1GB - which is way loads for normal setups. Any more physical RAM over 3GB gets assigned to Windows rather than apps, and essentially just sits there unused.

So, in a normal desktop / workstation 32bit Windows machine, 3GB of physical RAM is the most that is useful. If you put in 4GB, anything you're lucky enough to get above 3GB gives you bragging rights but little else. Your applications can't use it, and Windows doesn't need it.

If you're moving to 64bit Windows soon, then 4GB of RAM (or more) makes sense. But if you *are *moving to 64bit Windows soon - good luck. ;-)