if i remember properly
ARM licenses some of there tech from AMD
AMD holds the x64 license,
ARM does good AMD does good as AMD receives money as well do to those licenses,
ARM entering the x64 market means AMD makes more money from ARM and of course gets money from Intel,
Another thing to consider is ARM entering the desktop and mobile sector means while they may not be as powerful as there competitor tablets and netbooks using ARM cpu could improve battery life even further without sacrificing features. forcing Intel and AMD to release even more competitive products,
right now AMD can get down to 9w -18w on a single - dual core low power APU in the 1-1.4ghz range
ARM has quadcore chips already that can fit in smartphone power requirments,
now they might not support all features other CPUs do, the key thing to remember here is games, movies, music, web browsing dont really need all those instructions set, meaning the typical end user in the near future could end up with an ARM quadcore that uses less then 10w but feels and functions the same as an Intel or AMD dual core- triple core in day to day tasks. as ARM is already capable of creating octo core RISC cpu.
so as it stands ARM can already products 8 core mobile chips that are low power, they can also already adress up to 1TB of memory if needed, alot of there tech is lic direct from AMD, so alot of AMD tech ARM has complete access to, should be fairly interesting to see what happens.