[phire]

They made SSE and SSE2 extensions part of the core instruction set in AMD64.

But they didn't remove x87. It's not really used, compilers only emit it when code asks for a long double.

Personally, I do think they should have banned x87 from 64bit code. But it wouldn't have allowed them to remove the x87 units from the chip, as every AMD64 chip to this day still supports 32bit compatibility mode, and regularly uses it.