quote: Let me make this perfectly clear, there are two instruction sets that are "common" in CPUs right now (one is FAR more common), x86 and x64. There is ONE architecture implements x64 instruction set, the Itanium (well and Itanium 2). There are boatloads of CPUs (even ones sold at best buy) that support extended x86 (AKA x86-64).
quote: x86 is "32 bit". x86-64 is 32 bit instruction set with ability to address 64 bits (2^64) of RAM.