Chip Showdown: A Guide to the Best CPUs

CPU Terms

Illustration by Harry Campbell
Discussions of CPUs can quickly sound pretty technical. Here are some of the most-common terms used in describing processors.

Cache: Internal memory in the CPU, housing frequently accessed data and instructions for superfast turnaround on memory requests.

Chipset: Components that work together, alongside the CPU, to form a cohesive computing unit.

Clock speed: The speed at which a CPU executes its instructions, usually measured in gigahertz (billions of cycles per second); also known as the chip's "frequency."

Code name: A company's nomenclature for a new series of chips; may refer to a processor lineup ("Gulftown" or "Deneb"), a microarchitecture (Intel's "Nehalem"), or a platform (AMD's "Dragon").

Core: The part of the processor that reads and executes program instructions.

Die: The physical surface area on which a semiconductor circuit is fabricated. Smaller die sizes re­­duce chip manufacturing costs and chip power consumption.

GPU: Graphics processing unit-the chip that processes graphics and video. It may be located on the CPU, as part of the motherboard chipset, or on a separate ("discrete") graphics card.

Nanometer: One billionth of a meter; the unit used to gauge the distance between the narrow connections tying transistors on a CPU.

Socket: The electrical interface on the motherboard, where the CPU sits; usually backward-compatible over chip iterations.

New Technology on the Horizon

Illustration by Harry Campbell
What does the future of CPU technology look like? In a word, integration. Expect Intel to push toward stronger integration of its CPUs and GPUs, as in its Core i3 and i5 lines. The 32-nanometer Sandy Bridge CPU is the next "tock" in the company's "tick/tock" development strategy, in which it refines the microarchitecture on one hand and launches a brand-new design on the other. Beyond Sandy Bridge is the 22-nanometer Ivy Bridge.

On Sandy Bridge processors, the GPU will actually rest on the same hunk of silicon as the CPU-right now, the Core i3, i5, and i7 platform features a 45-nanometer graphics core that's split onto a separate die. A new Advanced Vector Extension instruction set-an evolution of the set for Nehalem processors-should bring performance boosts to media encoding, 3D modeling, and video and audio processing.

AMD also plans to get into the CPU/GPU mash-up party (it bought GPU and chipset developer ATI Technologies in 2006). Its forthcoming microprocessor design, code-named Fusion, will come in two varieties. Llano will be a 32-nanometer quad-core design featuring a DirectX 11- compatible GPU, similar to the ATI Radeon 5000. Ontario is a 40-nanometer design that blends a two-core CPU and a DirectX 11 GPU together for ultra-low-power mobile processing-a direct shot at Intel's Atom platform.

Llano chips should continue AMD's Turbo Core automatic overclocking. But to lower the power draw of its chips, the company is developing a new power-gating technology to let individual cores shut down when not needed.

Server Chips

Illustration by Harry Campbell
Have you ever considered using a server-class processor as the heart of your desktop PC? Depending on the kind of system you're after, you might unlock even more computer power if you opt for a server-class chip instead of a consumer CPU. But you may have to fork over some extra cash for it and consider how it affects your overall system configuration.

Intel's Xeon-class processors can be powerful substitutes for a regular CPU--a Xeon W3580 can go onto an analogous LGA 1366-socket motherboard. The W3580 costs the same as its consumer equivalent, the Core i7-975 Ex­­treme Edition, and it comes with support for both server-grade Error Correction Code memory and triple-channel memory up to 1333GHz speeds.

As for AMD, you could opt for one of its latest 8- or 12-core Opteron CPUs ($1000-plus for the 12-core variant). You'll have to pick up a G34-socket motherboard, as no server chip is directly compatible with a Socket AM2+ or AM3 design. A six-core Opteron chip might offer faster clock frequencies, but it will be a pricer option, and one that requires a Socket F motherboard. AMD's $300 "Thuban" line of consumer CPUs may be a better option.

Phone CPUs & Specs

Illustration by Harry Campbell
What's inside your smartphone or tablet? Consumers are increasingly spending time with the computer in their pocket, rather than their laptop. As smartphones and tablets become more and more capable for both work and play, we thought no discussion of processors would be complete without considering the latest mobile offerings. So we looked at the processors in many popular smartphones and tablets, ranking them, in our estimation, from most powerful to least.

This chart (click on the thumbnail at left) starts with a column of processor models. Most smartphone and tablet processors are SoCs (System-on-Chip designs), meaning that they combine CPU, graphics, RAM, and often other features into a single multilayered package. So we list the actual CPU within each SoC, its clock frequency, its GPU, and representative products with those internals. Individual products may slightly vary the specs (increasing or decreasing CPU clock speed, or the amount of RAM, for example). In most cases, products are readily available, but a couple of the mobile processors have only recently been an­­nounced, with no shipping products yet named for them.

--Joel Durham Jr.

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