Advanced Micro Devices Inc (AMD)

[Haddock]

If P4 can multiply 64-bit floating-point as fast as A64 can

Faster, actually, at least in 32 bit mode. For 64 bit mode there may be apps that benefit from the extra registers enough to make up for the MHz deficit.

But there was a game designer who wanted to use huge amounts of linearly addressable RAM to design 3D worlds for games (not for playing them). Forget the name, but he was enthusiastic about x86-64.