Physical Address Extension (PAE) is a feature to allow 32-bit x86 processors to access a physical address space (including random access memory and memory mapped devices) larger than 4 gigabytes.
Currently if you run a 32bit windows server oracle can only allocate 4 GB, but you have to enable a PAE function in Windows 2008 in order to fully use the memory provided.
In cmd run As Administrator: ‘Bcdedit /set PAE forceenable’ to see if it works or if you are restricted. run: ‘bcdedit /enum >bcd.txt’ registry entry
sadly PAE seems to not work in standard editions. It’s always better to migrate your oracle server to a 64 bit environment for better performance, especially in newer versions like 11G because 11G tends to use a lot more memory then the 10G versions.