Re: missing the point
And x86 continues to be backward compatible even if certain things (like MMX and the FPU) are as near as makes no difference emulated nowadays (in particular, code mixing MMX and SSE will take a performance hit due to register sharing). This is about (software in) the OS compiled to require a higher baseline ISA than the one provided by OG Athlon64/64 bit enabled Pentium 4. You can (still[1]) run your old software on the new OS, assuming your CPU is new enough, or continue to run an old OS on an old (or new) CPU.
[1]: The 800lbs gorilla of 32bit libraries is Wine, and it's tantalizingly close to drop that requirement (nearly all 32bit wine libs can be linked against 64 bit versions of their respective native library dependencies, and work is ongoing to close that gap). Once that is achieved, I don't see many binary distributions maintaining proper multilib support on amd64.
Biting the hand that feeds IT
