Opteron/ Athlon64

AMD’s 8th generation CPU was released in 2003. It is based on a completely new core called Hammer.

A new series of 64-bits processors is called Athlon 64, Athlon 64 FX and Opteron. These CPU’s has a new design in two areas:

The memory controller is integrated in the CPU. Traditionally this function has been housed in the north bridge, but now it is placed inside the processor. AMD introduces a completely new 64-bit set of instructions. Moving the memory controller into the CPU is a great innovation. It gives a much more efficient communication between CPU and RAM (which has to be ECC DDR SDRAM – 72 bit modules with error correction).) Every time the CPU has to fetch data from normal RAM, it has to first send a request to the chipset’s controller. It has to then wait for the controller to fetch the desired data – and that can take a long time, resulting in wasted clock ticks and reduced CPU efficiency. By building the memory controller directly into the CPU, this waste is reduced. The CPU is given much more direct access to RAM. And that should reduce latency time and increase the effective bandwidth. The Athlon 64 processors are designed for 64 bits applications. This should be more powerful than the existing 32 bit software. We will probably see plenty of new 64 bit software in the future, since Intel is releasing 64 bit processors compatible with the Athlon 64 series.

Figur 114. In the Athlon 64 the memory controller is located inside the processor. Hence, the RAM modules are interfacing directly with the CPU.

Overall the Athlon 64 is an updated Athlon-processor with integrated north bridge and 64 bits instructions. Other news are:

Support for SSE2 instructions and 16 registers for this. Dual channel interface to DDR RAM giving a 128 bit memory bus, although the discount version Athlon 64 keeps the 64 bit bus. Communikationen to and from the south bridge via a new HyperTransport bus, operating with high-speed serial transfer. New sockets of 754 and 940 pins.