AMD's 64-bit CPUs. Announced in 1999, AMD was first to add 64-bit capability to the x86 architecture with the introduction of the Opteron in 2003. Following very quickly, Intel added AMD's 64-bit architecture to its x86 family (see
x86-64).
Direct Connect Architecture
The AMD64 design, known as the Direct Connect Architecture (DCA), includes a set of 64-bit instructions as well as 64-bit registers that allows the CPU to address more than 4GB of memory, which is the limit of 32-bit registers. It also added a DDR memory controller directly on the CPU chip for increased performance. See
Opteron,
Athlon,
Sempron,
Turion and
AMD64 sockets.