Re: Xbox 360 / DX10 ?
DX9c did not enable a geforce 3 to run SM3.0, and DX10 will not allow the Xbox to run anything the hardware doesn't support. The xbox360's api supports all of the chips features already. If the R500 supported SM4, the xbox360's api would have allowed game developers to use it from the very beginning. If not, it can never be enabled. Anyway to slice it, Microsoft isn't holding back on the xbox's capabilities through software.
Have the courage to play devil's advocate, you'll be amazed with what you can learn about your enemy and yourself.