ICM – Core 2 Duo
Intel Core Microarchitecture is, as previously related, sort of a combination of the P6 marchitecture used in the Pentium III, and the Intel NetBurst marchitecture used in the Pentium 4. It combines existing features from P6 that lend to its more energy and time efficient design, as well as features from NetBurst that allow higher levels of performance. Before touching on each new innovation, here is a list of features that will be discussed:

• Intel Wide Dynamic Execution
• Intel Intelligent Power Capability
• Intel Advanced Smart Cache
• Intel Smart Memory Access
• Intel Advanced Digital Media Boost

Wide Dynamic Execution is Intel’s name for the system of decoders and execution cores used by ICM. While all processors have their Execution system, P6 had primitive dynamic execution and NetBurst had the Advanced Dynamic Execution Engine, Wide Dynamic Execution is a large step in right direction in terms of power efficiency and overall performance. Essentially what Intel has done is, as the name suggest, widened each execution core. This allows more instructions to be handled simultaneously, four rather than the three found in P6 and NetBurst. More specifically, Intel’s improvements focus around the implementation of more accurate branch prediction and deeper instruction buffers (where instructions sit before entering the execution core).

The most significant development here is something called “macrofusion”. Intel uses what they call macrofusion to combine common instruction pairs into something called a micro-op to be sent through the decoder to the execution core together at the same time. Previously, each instruction was sent through the decoder to the execution core by itself, even if a similar instruction was waiting right behind it. So by using macrofusion, Intel’s Wide Dynamic Execution engine increases the amount of instructions that can be sent to the execution core in any given period of time. This increases efficiency, which in turn increases performance and decreases power usage. Combine this with an upgraded algorithmic logic unit (ALU), and ICM has quite a powerful branch prediction/execution engine at its disposal.

In most current processors, all of the logic subsystems on the die are turned on at all times, whether they are being used or not. In ICM, Intel implements advanced power gating that allows each logic subsystem to be turned on only when it needs to be used. This means that the rest of the logic subsystems are turned off, or in some kind of hibernation mode, while they are not being used. The result is a significant decrease in overall power consumption, which of course further increases efficiency. This means that ICM uses much less power than traditional processors, making it the ideal platform for mobile computing. Intel’s name for these features is Intelligent Power Capability.