Incorrect. A 32 bit OS cannot go beyond 4GB of addressable memory, ever. And it has nothing to do with the developers coding support for more than 4 in the OS.
Why? A 32-bit register means that 2^32 addresses, or 4 gigabytes worth, can be referenced. This is a hard, mathematical limitation. This 4GB includes system memory, video RAM, and any onboard memory - anything that uses an address. This is why users see less than 4 if that's what they installed. What happens is the OS assigns addresses in order of importance: whatever's on the Mobo, then Video, and then the installed DIMMS. What you see displayed as usable is the value of your physical RAM less Video and onboard.
You may be able to put more physical RAM on the Mobo, but you cannot use it.
To use more than 4GB total addressable memory, you much go to a 64bit OS. That gives 2^64 (17,179,869,184 gigabytes) of addressable space.