The terms these days are synonymous, since any contemporary consumer-grade x86 processor is expected to be 64-bit-capable. Perhaps the one exception is the low-power chips such as the Atom where efficiency takes precedence over performance. Anyway, like I said before, compatibility relies on being able to perform certain techniques that Intel has patented. They sure as blank can't go to AMD since it's a direct competitor (they now possess ATI, nVidia's chief GPU rival). And Intel won't grant the license itself because they're horning into nVidia's market itself with Larabee, making them direct competitors also.