Upgrading And Repairing PCs 21st Edition: Processor Features

Intel Core ix-Series And Atom Processors

The Core i processor family replaced the Core 2 and includes two different microarchitectures: The first generation of Core i processors is based on the Nehalem microarchitecture, and the second generation uses Sandy Bridge microarchitecture.

Nehalem Architecture

The Nehalem microarchitecture’s key features include the integration of the memory controller into the processor, and in some models, the entire northbridge including an optional graphics processor in a separate core on the processor die. The first Core i-series processor was the Core i7 introduced in November 2008. Initially built on a 45 nm process, later Core i-series processors were built on an improved 32 nm process allowing for smaller die, lower power consumption, and greater performance. All support DDR3 memory and include L3 cache, and some models include support for HT Technology. See the following table for details.

There are two main variants in the first-generation (Nehalem) Core i-series Family: high-end versions that use Socket LGA 1366 and more mainstream models that use Socket LGA 1156. The latter mainstream models include a fully integrated northbridge, including a dual-channel DDR3 memory controller, graphics interface, and even an optional full-blown graphics processor. Because the entire northbridge functionality is integrated into the processor, Socket LGA 1156 chips use a slower 2 GB/s DMI as the FSB connection to the Platform Controller Hub component on the motherboard.

Core i 900-series processors using Socket LGA 1366 include a triple-channel DDR3 memory controller and a high-performance FSB called QPI (Quick Path Interconnect) that connects to the northbridge component (called an I/O Hub or IOH) on the motherboard. The IOH implements the PCIe graphics interface.

Core i7 and i5 processors also support Turbo Boost (built-in overclocking), which increases the performance in heavily loaded processor cores while reducing performance to cores that are lightly loaded or have no work to perform. Turbo Boost is configured through the system BIOS.

The table below lists the Intel Core i-series family processors using Nehalem microarchitecture:

* This CPU core also used by Pentium Processor G6950-60

The initial members of the Core i-series family included the Core i5 and i7 processors. These were later joined by the low-end i3 processors.

Sandy Bridge Architecture

Intel introduced the second generation of Core i-series processors, those based on the Sandy Bridge microarchitecture, in January 2011. The Sandy Bridge microarchitecture includes, as its predecessor did, an integrated memory controller and northbridge functions.

However, Sandy Bridge has many new features, including an in-core graphics processor on some models; the new AVX 256-bit SSE extensions; a new instruction cache for holding up to 1500 decoded micro-ops; a more accurate branch prediction unit; the use of physical registers to store operands; improved power management; Turbo Boost 2.0 for more scaled responses to adjustments in core usage, processor temperature, current, power consumption, and operating system states; and a dedicated video decoding/transcoding/encoding unit known as the multi-format codec (MFX). All Sandy Bridge processors use a 32 nm manufacturing process.

The table below lists the Intel Core i-series family processors using Sandy Bridge microarchitecture:

Sandy Bridge processors using LGA 2011 processor sockets are classified as Sandy Bridge-E.

Sandy Bridge also includes Pentium processors in the 967-997, B940-B980, G620-G645T, and G840-G870 series. These processors feature lower clock speeds, less powerful integrated GPUs, and smaller cache sizes than Core i processors. Celeron processors in the B720, 847E, 787-797, 807-887, B710, B800-B840, G440-G465, and G350-G555 series are also based on Sandy Bridge but feature smaller cache sizes and slower clock speeds than Pentium processors based on Sandy Bridge.

Ivy Bridge Architecture

Intel introduced the third generation of Core i-series processors, those based on the Ivy Bridge microarchitecture, in April 2012. The Ivy Bridge microarchitecture represents an improved version of the Sandy Bridge microarchitecture. Ivy Bridge features support for PCI Express 3.0, a new fabrication process at 22 nm, lower power consumption, support for low-voltage DDR3 memory, and support for DirectX 11 graphics with integrated HD Graphics 4000. Existing Sandy Bridge motherboards can use Ivy Bridge CPUs, but a BIOS update might be needed in some cases. The following table lists Core i-series processors using Ivy Bridge microarchitecture.

The table below lists Intel Core i-series family desktop processors using Ivy Bridge microarchitecture:

Processors with power levels below 35 W are also available but not listed here.

Pentium processors in the G2100 series also use the Ivy Bridge microarchitecture but feature smaller cache sizes and have only two cores without HTT, compared to Core i3’s four cores with HTT.

Intel Atom

Intel introduced its Atom ultra low power processors in 2008 and refreshed the line with new models with integrated graphics (D25xx series) in 2012. Although a few vendors have created very low-end desktop computers using Atom, this processor is designed primarily for netbooks, tablets, home servers, and other specialized uses. It is a 64-bit processor fully compatible with x86 and 64-bit versions of Windows and other operating systems, and some models support HT Technology. However, it supports only SSSE3 instructions, has a 4 GB memory limit, and includes only two cores.