"Red Hat has been partnering with chip vendors AMD and Intel for a long time. Every so often though Red Hat will announce something specific with one vendor (or the other)--that's the case with the announcement today on a speed/functionality announcement with AMD's processors running on HP hardware with Red Hat Enterprise Linux 5.
"Red Hat is announcing that users can, '...achieve significant performance gains by coupling new high-performance device drivers with the features provided by Quad-Core AMD Opteron processors, available with HP ProLiant DL585 G5 servers...'"