You'll never have access to a full 4GB of RAM on a 32-bit OS. The entire address space is 4GB, of which some is hardware. 3.5GB is as good as it gets.
that is total bullsh1t. When you patch your kernel to allow the PAE extension to function. If you have 4GB installed. Then all but 3MB, yes, 3MB is the reserve for hardware. The rest is usable RAM. There are too many wana be smart asses out here on the net that may remember word for word what they have read, but they havent done shit. They obviously are not the right people to ask if they just take what they are told. That is not my idea of a person of reference.
FYI 32bit Windows servers average 64GB of RAM on the high end. And on the low side you would see something around 12GB. Dont try to pollute peoples minds with your virgin experiences.