CORE i7 PROCESSOR FEATURES

The Core i7 is a CPU series manufactured by Intel aimed at high-end computers. In this tutorial, we will present a series of quick reference tables for you to compare the main differences between all models released so far.
Currently, there are two different generations of this CPU around, using a completely different internal microarchitecture. The 6xx, 7xx, 8xx, and 9xx models are based on the “Nehalem” microarchitecture and also known as “first generation,” while the 26xx, 27xx, 28xx, and 29xx models are based on the “Sandy Bridge” microarchitecture and also known as “second generation.”
In the past, Intel processors used an external memory controller located in the north bridge chip (also known as Memory Controller Hub, MCH). This means that with CPUs using this older architecture, the chipset (and therefore, the motherboard) is the component that sets the type and amount of memory you can install in the computer. With the Core i processor line, the memory controller is embedded in the CPU, and it is the processor (and not the chipset) that sets the memory type and amount you may have installed in your system. The motherboard, however, may have a limitation on the amount of memory you can install.
The memory controller integrated in the Core i7 accepts only DDR3 memories, supporting the now standard dual-channel (triple-channel on socket 1366 models) architecture up to 1.6 V. Memory modules which require voltages higher than this will not work and may even damage the processor. The speeds supported will depend on the CPU model, as we will present in the next pages.
Socket 1366 models use a triple-channel memory architecture, meaning that they access three memory modules at the same time. So, with these CPUs, you must install at least three memory modules in order to reach the maximum performance they can provide. This architecture provides a 50% bandwidth increase compared to the dual-channel architecture. For example, DDR3-1066 memories working in dual channel mode have a maximum theoretical transfer rate of 17 GB/s, while if working in triple channel they have a maximum theoretical transfer rate of 25.5 GB/s.
Core i7 CPUs (except socket 1366 models) also have an embedded PCI Express 2.0 controller, so with these processors, the video card is connected directly to the CPU, which in theory can improve the practical bandwidth achieved. These CPUs can access one video card at x16 transfer rate or two at x8 speed each. Because in these models the PCI Express 2.0 controller is integrated inside the CPU, Intel decided to use a lower-speed bus called DMI (Digital Media Interface), which operates at 1 GB/s (first-generation Core i7) or 2 GB/s (second-generation Core i7) in each direction, to connect the CPU to the chipset. This bus was used to connect the north bridge chip to the south bridge chip on previous chipsets from Intel. The lower bandwidth isn’t a problem, since a high-bandwidth bus is no longer needed given that the video card and memory are now connected directly to the CPU.
Socket 1366 models don’t have this embedded PCI Express 2.0 controller, and this component is located in the north bridge chip from the chipset. Because of that, it uses a high-speed bus called QuickPath Interface (QPI) to be connected to this chip. This bus works at 2.4 GHz (4.8 GB/s) on Core i7 and 3.2 GHz (6.4 GB/s) on Core i7 Extreme processors.
Some Core i7 models have an integrated video controller. On these models, the on-board video is controlled by the CPU and not by the motherboard chipset.
Core i7 CPUs have a base clock from which all other clocks are derived. The default base clock is 133 MHz for all first-generation models and 100 MHz for all second-generation models.
Core i7 processors have Turbo Boost technology, which is an automatic overclocking feature (i.e., the CPU increases its clock rate above the official number when it “feels” that the system is requiring more processing power).
The main technical features of Core i7 processors include:

• Nehalem (6xx, 7xx, 8xx, and 9xx) or Sandy Bridge (26xx, 27xx, 28xx, and 29xx) microarchitecture
• 64 KB L1 cache (32 KB data + 32 KB instruction) per core
• 256 KB L2 cache per core (renamed to “mid-level cache” or “MLC” in the Sandy Bridge microarchitecture)
• Between 4 MB and 12 MB shared L3 cache memory (renamed to “last-level cache” or “LLC” in the Sandy Bridge microarchitecture), depending on the model
• Dual-core, quad-core and six-core technology
• Socket 1156 or 1366 on Nehalem-based desktop models, socket 1155 on Sandy Bridge-based desktop models, socket 988 or 1288 on Nehalem-based mobile models, socket 988, 1023 and 1224 on Sandy Bridge-based mobile models
• DMI bus (1 GB/s per direction on Nehalem-based models or 2 GB/s per direction on Sandy Bridge-based models), except on socket 1366 models
• QPI bus on socket 1366 models
• Integrated memory controller supporting DDR3 memories in dual- or triple-channel architecture (see next pages for supported speeds)
• Integrated PCI Express 2.0 controller (one x16 lane or two x8 lanes), except socket 1366 models
• Integrated DirectX 10 (Nehalem-based models) or DirectX 10.1 (Sandy Bridge-based models) video processor
• Intel Turbo Boost Technology
• Virtualization technology
• Intel EM64T technology 
• Hyper-Threading (HT) technology
• SSE4.2 instruction set
• AES-NIS instruction set
• AVX (Advanced Vector Extensions) instruction set (Sandy Bridge models only)
• Execute Disable Technology
• Enhanced SpeedStep Technology
• 45-nm or 32-nm manufacturing process

For a more detailed explanation about the Core i7 processors with all the differences between the Nehalem microarchitecture and the Sandy Bridge microarchitecture, please read our “Inside the Intel Nehalem Microarchitecture” and “Inside the Intel Sandy Bridge Microarchitecture” tutorials.