I said that it mattered years ago, and doesn't matter now. Also, I wasn't talking about backwards compatibility, at least not directly. ISA matters a great deal

I said that it mattered years ago, and doesn't matter now. Also, I wasn't talking about backwards compatibility, at least not directly. ISA matters a great deal for compatibility and software, but not at all for performance as of the past decade or so. None of the x86 lock-in tactics I describe above would be possible if ISA didn't matter at all -- it just doesn't matter for performance/watt.