Couldn't software be compiled for different processors, like on the Amiga. Then one version would be optimised for MMX processors but another version that still runs on basic ARM code. It would also work as an insentive to upgrade in order to improve the performance for that software by enabling the MMX extentions. Also, are there any other new instructions that ARM have added since 610/710/StrongARM? I find it hard to believe they just left it!