It seems to be slightly better than for Windows....
First - no 32 bit OS can ever address more than 4GB (don't get confused by the concept of virtual memory)
Second - some memory addresses are reserved for things like the PCI bus
This leaves us with 3GB to 3.5GB usable memory
Third - some hardware cannot handle that much memory, so you have to check hardware restrictions as well
Don't fix it if it ain't broken, don't break it if you can't fix it