AMD Opteron (1)

The Opteron is AMD's x86 server processor line, and was the first processor to implement the AMD64 instruction set architecture (known generically as x86-64). It was released on April 22, 2003 with the SledgeHammer core (K8) and was intended to compete in the server market, particularly in the same segment as the Intel Xeon processor. Processors based on the AMD K10 microarchitecture (codenamed Barcelona) were announced on September 10, 2007 featuring a new quad-core configuration.

Two key capabilities

Opteron combines two important capabilities in a single processor die:
native execution of legacy x86 32-bit applications without speed penalties
native execution of x86-64 64-bit applications

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 makers (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 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 AM2/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. Thus the Opteron is a Non-Uniform Memory Access (NUMA) architecture. 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 allows the CPU to access local RAM very 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 2005, AMD introduced its first "Multi-Core" Opteron CPUs. At the time, AMD's use of the term "Multi-Core" in practice meant "dual-core"; each physical Opteron chip contained two separate processor cores. This effectively doubled the computing-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. Because motherboard costs increase dramatically as the number of CPU sockets increase, multicore CPUs enable a system of higher performance to be built at lower cost.

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.

Second-Generation AMD Opteron processors are offered in three series: the 1000 Series (up to 1P/2-core), the 2000 Series (up to 2P/4-core), and the 8000 Series (4P/8-core to 8P/16-core). The 1000 Series is built on AMD's new Socket AM2. The 2000 Series and 8000 Series are built on AMD's new Socket F.

AMD launched its Third-Generation Quad-core[1] Opteron chips on September 10th, 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].


Socket 939

AMD has also released Socket 939 Opterons, reducing the cost of motherboards for low-end servers and workstations. Except for the fact they have 1 MiB L2 Cache (versus 512 KiB for the Athlon64) the Socket 939 Opterons are identical to the San Diego and Toledo core Athlon 64s, but are run at lower clockspeeds than the cores are capable of, making them more stable. They are also the only dual core Socket 939 processors still easily available now that the Athlon 64 X2s for that platform have been discontinued, though even these processors are becoming more and more difficult to find. [1]


Socket AM2
Socket AM2 Opterons are available for servers that only have a single-chip setup. These chips may prove to be as successful as the previous generation socket 939 Opterons due to the Opteron's overclockability. Codenamed Santa Ana, rev. F dual core AM2 Opterons feature 2×1 MiB L2 cache, unlike the majority of their Athlon 64 X2 cousins which feature 2x512 KiB L2 cache.


Socket F

Socket F (LGA 1207 contacts) is AMD’s second generation of Opteron socket. This socket support processors such as the Santa Rosa, Barcelona and Shanghai codenamed processors. The “Lidded Land Grid Array” socket adds support for DDR2 SDRAM and improved HyperTransport version 3 connectivity. Physically the socket and processor package are nearly identical, although not generally compatible with socket 1207 FX


Micro-architecture update

The Opteron line saw an update with the implementation of the AMD K10 microarchitecture. New processors, launched in the third quarter of 2007 (codename Barcelona), incorporate a variety of improvements, particularly in memory prefetching, speculative loads, SIMD execution and branch prediction, yielding an appreciable performance improvement over K8-based Opterons, within the same power envelope.[4]

In the meantime, AMD has also utilized a new scheme to characterize the power consumption of new processors under "average" daily usage, named Average CPU Power (ACP).nice posting bro