AMD Opteron (Denmark, Italy, Egypt, Santa Ana, Santa Rosa) processors
Introduction: May 2005 (Denmark, Italy and Egypt), August 2006 (Santa Ana and Santa Rosa)
The Opteron was 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.
The Denmark, Italy, Egypt, Santa Ana and Santa Rosa cores
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 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. 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 2.2GHz each. AMD's fastest single-core Opteron at this time was the model 252, with one core running at 2.6GHz. 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.
Source: Wikipedia, the free encyclopedia.