64-bit can make use of up to 8 GBs of RAM, the 32-bit pae kernel will recognize up to 6 GBs. Most Linux users will never need 8 GBs of RAM, ever. I had a 64 bit laptop not too long ago, always installed 32-bit distro's and never had an issue. I even had problems with 64-bit editions that weren't present in 32-bit.