Intel Dual Core Technology
By Gabriel Torres on May 17, 2005

Introduction

Intel has also recently announced its dual-core technology for their processors. Two new CPUs for the desktop market were announced: Pentium D, which is the dual-core version of Pentium 4, and Pentium Extreme Edition, which is the dual-core version of Pentium 4 Extreme Edition. As you can see, the dual-core processors aren't called "Pentium 4" as one should expect.

Together with these two new processors two new chipset series were released, i945 and i955. The current Intel chipsets aren't compatible with dual core technology because they don't support multiprocessor systems. So, even if you have a high-end socket 775 motherboard based on the latest Intel 925X chipset it won't be compatible with the new dual-core Pentium processors. To upgrade your system you will need to replace the motherboard as well.

Before we talk more in depth about these new processors and chipsets, let's take a look on Intel's roadmap on dual-core technology, shown on Figures 1 and 2. As you can see, Intel plans to put dual-core (or even more cores) in all their processor lines, from notebooks to servers.

Intel Dual Core
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Figure 1: Intel's roadmap on multi-core.

Intel Dual Core
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Figure 2: Intel's roadmap on multi-core.

Intel expects that by the end of 2006 70% of the desktop maket will be of dual-core processors.

Intel Dual Core
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Figure 3: Intel's forecast on multi-core market share.

A Look Inside Intel's Dual Core Technology

The most interesting thing about Intel's dual core tecnology is how it is manufactured. With the tecnology available today for manufacturing processors, called 90 nm, the silicon chips for dual core CPUs must be "together", i.e. side-by-side and cut together from the wafer. You can see this on the left side of Figure 4. This is the tecnology that the announced processors use.

With the future 65 nm technology it is possible to manufacture each silicon chip separately and then put them together, i.e. it will be possible to pick each silicon chip from different positions of the wafer, not requiring them to be originally together. This is what you see on the right side of Figure 4. This manufacturing process is more efficient and will be available on first half of 2006, using a 2 MB memory cache of each core.

Intel Dual Core
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Figure 4: A look inside Intel's dual core technology.

Pentium D


Simply put, Pentium D is a Pentium 4 with dual-core technology. But there is a very important difference between Pentium 4 and Pentium D besides this new technology. The new Pentium D doesn't have Hyper-Threading technology. Yes, you read it right. Hyper-Threading makes the operating system to think that there are two CPUs installed on the system. Thus, when you use a Pentium 4 with this technology, Windows XP recognizes it as if two CPUs were installed on the system. Read our tutorial about this subject.

So, when you use a Pentium D, the operating system will recognize two CPUs, and not four as it would happen if this new processor had Hyper-Threading tecnology.

Of course having two real CPUs is far more efficient than using Hyper-Threading technology, which is just an emulation of having two CPUs on the system, using idle parts of the CPU to perform this emulation.

Three Pentium D models were announced:

All of them use a 800 MHz external bus and use the Intel 64-bit extensions (EM64T), so they are based on Pentium 4 6xx series.

Pentium Extreme Edition

On the regular Pentium 4 processors the difference between Pentium 4 and Pentium 4 Extreme Edition is the presence of a larger L2 memory cache on the later. But for the new dual-core processors (8xx series) the difference between the two is the presence of the Hyper-Threading technology, which is available only on Pentium Extreme Edition.

So, with a Pentium Extreme Edition in your system your operating system will recognize four CPUs, since each core will be recognized as two CPUs because of the Hyper-Threading technology.

So far just one Pentium Extreme Edition model was announced: Pentium Extreme Edition 840, running at 3.2 GHz and with 1 MB L2 memory cache for each core. As you can see, this CPU is exactly the same Pentium D 840 but with Hyper-Threading technology.

Intel Dual Core
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Figure 5: Pentium Extreme Edition 840.

New Chipsets: i945 and i955

The i915 and i925 chipsets series don't recognize more than one CPU, thus are incompatible with dual core CPUs. So, Intel had to release new chipsets, the 945 and 955 series. Intel 955X is target to Pentium Extreme Edition, while Intel 955 is targeted to Pentium D and Intel 945 is targeted to the entry-level market.

Actually only Intel 955X chipset was officially released. This chipset works at 800 MHz or 1,066 MHz, supports dual channel DDR2 up to DDR2-667 memories and up to 8 GB, 7.1 high definition audio, four Serial ATA II at 300 MB/s supporting RAID (0, 1, 5 and 10), Active Management Tecnology, Flex Memory Technology (which allows DDR dual channel configuration with modules with different capacities), one x16 PCI Express slot (2 slots if using a bridge chip) and up to six x1 PCI Express slots.

Intel Dual Core
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Figure 6: Intel 955X chipset.

So far what we know is that the forthcoming Intel 945G will have a new integrated graphics called GMA 950 (integrated graphics from Intel 915G is GMA 900), GMA standing for Graphics Media Accelerator.

Originally at http://www.hardwaresecrets.com/article/140

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