From AMD's suit against Intel. Perhaps relevant to some PG/AMD issues.
"...125. Intel has designed its compiler purposely to degrade performance when a program
is run on an AMD platform. To achieve this, Intel designed the compiler to compile code
along several alternate code paths. Some paths are executed when the program runs on an Intel
platform and others are executed when the program is operated on a computer with an AMD
microprocessor. (The choice of code path is determined when the program is started, using a
feature known as "CPUID" which identifies the computer's microprocessor.) By design, the
code paths were not created equally. If the program detects a "Genuine Intel" microprocessor,
it executes a fully optimized code path and operates with the maximum efficiency. However,
if the program detects an "Authentic AMD" microprocessor, it executes a different code path
that will degrade the program's performance or cause it to crash..."
