AMD Opteron

The AMD Opteron (codenamed SledgeHammer during development) was the first of AMD's eighth-generation x86 processors based on the K8 or Hammer core, and the first processor to implement the AMD64 (formerly x86-64) instruction set architecture. It was released on April 22, 2003 and was intended to compete in the server market, particularly in the same segment as the Intel Xeon processor.

Technical description

The two key capabilities

Opteron combines two important capabilities in a single processor die:

1. native execution of legacy x86 32-bit applications without speed penalties
2. native execution of x86-64 64-bit applications (linear-addressing beyond 4 GB RAM)

The first capability is notable because at the time of Opteron's introduction, the only other 64-bit processor architecture marketed with 32-bit x86 compatibility (Intel's Itanium) ran x86 legacy-applications only with significant speed degradation. The second capability, by itself, is less noteworthy, as all major RISC players (Sun SPARC, DEC Alpha, HP PA-RISC, IBM POWER, SGI MIPS, etc.) have had 64-bit implementations for many years. In combining these two capabilities, however, the Opteron has earned recognition for its ability to run the vast installed base of x86 applications economically, while simultaneously offering an upgrade-path to 64-bit computing.

The Opteron processor possesses an integrated DDR SDRAM / DDR2 SDRAM(Socket F) memory controller. This both reduces the latency penalty for accessing the main RAM and eliminates the need for a separate northbridge chip.

Multi-processor features

In multi-processor systems (more than one Opteron on a single motherboard), the CPUs communicate using the Direct Connect Architecture over high-speed HyperTransport links. Each CPU can access the main memory of another processor, transparent to the programmer. The Opteron approach to multi-processing is not the same as standard symmetric multiprocessing as instead of having one bank of memory for all CPUs, each CPU has its own memory. The Opteron CPU directly supports up to an 8-way configuration, which can be found in mid-level servers. Enterprise-level servers use additional (and expensive) routing chips to support more than 8 CPUs per box.

In a variety of computing benchmarks, the Opteron architecture has demonstrated better multi-processor scaling than the Intel Xeon^{[citation needed]}. This is primarily because adding an additional Opteron processor increases bandwidth, while that is not always the case for Xeon systems, and the fact that the Opterons use a switched fabric, rather than a shared bus. In particular, the Opteron's integrated memory controller, when using Non-Uniform Memory Access (NUMA), allows the CPU to access local RAM quickly. In contrast, multiprocessor Xeon system CPUs share only two common buses for both processor-processor and processor-memory communication. As the number of CPUs increases in a Xeon system, contention for the shared bus causes computing efficiency to drop.

Multi-core Opterons

In May of 2005, AMD introduced its first "Multi-Core" Opteron CPUs. At the present time, the term "Multi-Core" at AMD in practice means "dual-core"; each physical Opteron chip actually contains two separate processor cores. This effectively doubles the compute-power available to each motherboard processor socket. One socket can now deliver the performance of two processors, two sockets can deliver the performance of four processors, and so on. Since motherboard costs go up dramatically as the number of CPU sockets increases, multicore CPUs now allow much higher performing systems to be built with more affordable motherboards.

AMD's model number scheme has changed somewhat in light of its new multicore lineup. At the time of its introduction, AMD's fastest multicore Opteron was the model 875, with two cores running at 2.2 GHz each. AMD's fastest single-core Opteron at this time was the model 252, with one core running at 2.6 GHz. For multithreaded applications, the model 875 would be much faster than the model 252, but for single threaded applications the model 252 would perform faster.

Next-Generation AMD Opteron processors are offered in three series: the 1200 Series (up to 1P/2-core), the 2200 Series (up to 2P/4-core), and the 8200 Series (4P/8-core to 8P/16-core). The 1200 Series is built on AMD's new Socket AM2. The 2200 Series and 8200 Series are built on AMD's new Socket F (1207).

AMD is expected to launch quad core^[1] Opteron chips in August 2007 ^[2] with hardware vendors to follow suit with servers in the following month. Based on a core design codenamed Barcelona, new power and thermal management techniques are planned for the chips. Existing dual core DDR2 based platforms will be upgradeable to quad core chips^[3].

Sumber:
http://en.wikipedia.org/wiki/Opteron