Parent: Processor Architectures

Update  2014 Feb

To better understand server systems, it is necessary to understand the microprocessors on which server systems are based. In turn, it is helpful to understand the recent history of microprocessors. The above links trace Intel processors from Pentium Pro to Haswell (1995-2014) The Intel Pentium Pro was a landmark that brought Intel into prominence in server systems. It was the first X86 (or IA-32) processor that shook the presumption that RISC was superior and would eventually take over the market.

The RISC argument had become so broadly accepted that Intel evens planned on replacing their X86/IA-32 line. Instead of fielding yet another RISC processor, Intel felt compelled to come up with an even better architecture that became EPIC, the foundation of the Itanium processors. There is a valid technical foundation to the argument that RISC concepts were becoming outdated. RISC was conceived with the anticipation of transistor budgets in the tens of thousands. In the EPIC/Itanium time frame, the transistor budget was in the tens of millions. Broad consensus does not seem to be a reliable predictor of the future.

New material will be below until they can be incorporated into the appropriate sections.

Ivy Bridge EP came in 2013 Q3. It was disclosed that there would be 3 distinct dies. The diagram below is from AnandTech, see references below

IvyBridgeDies

See Anandtech Intel's Xeon E5-2600 V2: 12-core Ivy Bridge EP for Servers by Johan De Gelas September 17 2013, and Intel Readying 15-core Xeon E7 v2,
SemiAccurate A technical look at Intel's new Ivy Bridge-EX,
and Toms Hardware Intel Xeon E5-2600 v2: More Cores, Cache, And Better Efficiency.

When the Ivy Bridge EP separate dies with 10 and 12 cores was announced, it seemed rather an unusual choice. Later, when the 15-core EX model was brought, it then became clear the 12-core E5 v2 actually shares a 15-core die with the E7 v2. Below is my rendering of the 3 Ivy Bridge EP dies that will be used in system architecture diagrams.

IvyBridgeDies

Presumably the 6-core die is to better support the lower price points.