What I understand about 32-bit OS is, the address is expressed in 32 bits, so at most the OS could use 232 = 4G memory space — I assume the unit is bytes, so 4GB.
Does this mean if any machine with a 32-bit OS (be it Windows or Unix) has more than 4GB total of RAM + page file on hard disk, for example 8GB RAM and 20GB page file, its memory will never be "used up"?
By "used up" I mean that increasing RAM or page file won't help the performance; of course, it's always possible an application will keep requesting memory from the OS but failing.
Similarly, if this 32-bit OS machine has 2GB RAM and 2GB page file, increasing the page file size won't help the performance. Is this true?