All About Core Processors

Intel Dual-Core CPU Overview

Dual-core refers to a CPU that includes two complete execution cores per physical processor. It combines two processors and their caches and cache controllers onto a single integrated circuit (silicon chip). It is basically two processors, in most cases, residing reside side-by-side on the same die. Dual-processor, Dual-core, and Multi-core: Keeping it straightDual-processor (DP) systems are those that contains two separate physical computer processors in the same chassis. In dual-processor systems, the two processors can either be located on the same motherboard or on separate boards. In a dual-core configuration, an integrated circuit (IC) contains two complete computer processors. Usually, the two identical processors are manufactured so they reside side-by-side on the same die, each with its own path to the system front-side bus. Multi-core is somewhat of an expansion to dual-core technology and allows for more than two separate processors. Taking Advantage of Dual-core TechnologyA dual-core processor has many advantages especially for those looking to boost their system's multitasking computing power. Dual-core processors provide two complete execution cores instead of one, each with an independent interface to the frontside bus. Since each core has its own cache, the operating system has sufficient resources to handle intensive tasks in parallel, which provides a noticeable improvement to multitasking. Complete optimization for the dual-core processor requires both the operating system and applications running on the computer to support a technology called thread-level parallelism, or TLP. Thread-level parallelism is the part of the OS or application that runs multiple threads simultaneously, where threads refer to the part of a program that can execute independently of other parts Even without a multithread-enabled application, you will still see benefits of dual-core processors if you are running an OS that supports TLP. For example, if you have Microsoft Windows XP (which supports multithreading), you could have your Internet browser open along with a virus scanner running in the background, while using Windows Media Player to stream your favorite radio station and the dual-core processor will handle the multiple threads of these programs running simultaneously with an increase in performance and efficiency. Today Windows XP and hundreds of applications already support multithread technology, especially applications that are used for editing and creating music files, videos and graphics because types of programs need to perform operations in parallel. As dual-core technology becomes more common in homes and the workplace, you can expect to see more applications support thread-level parallelism. Intel & AMD Dual-core Desktop ProcessorsThe Intel Pentium Processor Extreme Edition 840 running at 3.2 GHz and Intel 955X Express Chipsets are being built into computers that are now entering the market. This is Intel's first desktop dual-core product supporting Hyper-Threading Technology. Processor features include the following: Hyper-Threading Technology: Enables you to run multiple demanding applications at the same time. Intel Extended Memory 64 Technology: Provides flexibility for future applications that support both 32-bit and 64-bit computing. Dual-Core: Two physical cores in one processor support better system responsiveness and multi-tasking capability than a comparable single core processor. [Source: Intel Dual-core Desktop Processor] AMD also announced its line of desktop dual-core processors, the AMD Athlon 64 X2 processor family. The initial model numbers in the new family include the 4200+, 4400+, 4600+ and 4800+ (2.2GHz to 2.4GHz).The processors are based on AMD64 technology and are compatible with the existing base of x86 software, whether single-threaded or multithreaded. Software applications will be able to support AMD64 dual-core processors with a simple BIOS upgrade and no substantial code changes. [Source: AMD Dual-core Desktop Processor] Both companies have also announced or released dual-core processors for servers and workstations as well.

Intel Quad-Core CPU Overview and Roadmap

Intel is going to release their first quad-core desktop CPU in next November under the Core 2 Extreme series and in January 2007 mainstream quad-core CPUs will be released as Core 2 Quad. Let’s take a look on the technology and specs used by these new CPUs. First we need to talk about how multi-core CPUs are built. There are two approaches. On the first one, called “multi-chip”, each core is made by different chips that are put together in a single package. Pentium D is a good example of a dual-core CPU that uses this approach. On CPUs based on this technology when one of the CPU cores wants to talk with the other, it needs to go outside the CPU package, i.e. use the front side bus. Also the L2 memory cache is separated, thus when one core wants to access data stored on the cache of the other core, it need to access it thru the front side bus. Of course using the front side bus isn’t the best option, as the CPU runs internally faster than then front side bus. The second approach is called “monolithic”. Here the cores are already manufactured in only one chip. This is the technology used by Core 2 Duo CPUs, for example. When the CPUs want to talk to each other they don’t need to use the front side bus, as they were already built stuck together. Also, under this technology the memory cache is shared between the two cores. Performance wise this is the best option. On Figure 1 you see a summary of what we’ve just explained.

1: The two available approaches for building multi-core CPUs.

The new quad-core CPUs from Intel will mix both technologies. They will have two monolithic dual-core chips installed together in a single package. This means that cores 1 and 2 share the same memory cache, the same happening with cores 3 and 4. If cores 1 or 2 needs to talk with core 3 or 4 or to access the other cache, they will need to this externally, i.e. using the front side bus – which on the first models will be of 1,066 MHz. We drew a diagram illustrating this on Figure 2.


2: Intel approach for their first quad-core CPUs.








In November Intel will launch their first quad-core desktop CPU, called Core 2 Extreme QX6700. As you can see, it will be released under the Core 2 Extreme series, using the letter “Q” to indicate that it is a quad-core CPU. It will run at 2.66 GHz with a 1,066 MHz external bus, 8 MB total L2 cache (4 MB x 2) and will come with its overclocking protecting unlock, following the tradition of Intel’s Extreme series. The other specs continue to be the same as the rest of the Core 2 Duo family.
3: Core 2 Extreme QX6700 main specs.





On the same timeframe Intel will release their first quad-core Xeon CPU, Xeon 5300.
In January 2007 Intel will release Core 2 Duo CPUs with four cores and they will be named Core 2 Quad. So far Intel didn’t tell us what the models would be released. In the same timeframe Intel will also release a low voltage quad-core Xeon, which promises to dissipates 40% less power.
As for quad-core performance, we will be posting something about it during this week.