TECHiNSIGHT - Dual-Core Delivers Story

Home > Chipsets: The Building Blocks of Computing Story


	> Whitebook War II > Raid Controllers > Hardware Security > Torture On The Rack > What Matters

The Core Duo processor may be racking up most of the headlines in today's CPU world, but it's core logic that enables Core Duo to work its magic. In fact, core logic, a.k.a. the motherboard's chipset, is arguably the single-most important component of any PC. All of the processor advances, system bandwidth increases, new graphics interfaces, and so on don't matter at all if the chipset doesn't enable that functionality within the system.

In effect, the chipset is the central nervous system that binds a computer together and facilitates data transfer from one area to another. If you don't start a system's design here, you're beginning in the middle and are liable to miss some important value-add opportunities with your customer.

Bridge Basics

The two pieces of most modern chipsets, the northbridge and southbridge, govern distinct areas of system operation. The northbridge ties to the CPU, system memory, and graphics adapter (most recently via a wide PCI Express pipe). The southbridge generally feeds everything else, potentially including the integrated audio codec, network interface, PATA/SATA ports, PCI slots, USB ports, and a narrow PCI Express bus.

As you would expect, high-speed processing through the northbridge is paramount to system performance. The speed of the front-side bus (FSB), the pipe connecting the CPU and northbridge, and the memory interface speed are particularly important. This is one of the first things that enthusiasts will seek to overclock. Heading into the second quarter of 2006, FSB speeds for current core logic designs range from 667 MHz up to 1,066 MHz. The dual-channel DDR2 interface is capable of 10.7 GB per second--over 28 times the throughput of the 3 Gbps "SATA II" interface off the southbridge. Additionally, an increasing number of northbridges feature an integrated graphics processor (IGP)--essentially building in a low-end graphics card practically for free. Through IGPs, according to Mercury Research, by the end of 2005, Intel controlled 37% of the entire graphics market.

Naturally, high northbridge speeds and data bandwidth can require a substantial amount of power. This is why you see larger heatsinks planted on mainstream and performance northbridges compared to the southbridge, which often doesn't even require a heatsink. Overclocking increases this power strain even further. Many vendors, Intel included, have something of a don't ask, don't tell policy regarding overclocking, but be aware that if you do have a client with a mind toward stretching system performance, a higher-end heatsink or even watercooling may be an advisable upgrade.

The southbridge is sometimes undeservedly left out of chipset discussions, but this is where at least half of the innovation on today's PC platforms happens. For instance, the instant-on/off functionality required in Intel's Viiv initiative hinges on circuitry presently only found in the ICH7-DH southbridge. Similarly, the secondary HD Audio and Matrix Storage technologies reside in Intel southbridges. If the industry were to adopt a new add-in card technology or make Wi-Fi a de facto part of every PC, the southbridge is where those changes would be enabled.

Through licensing to companies including ATI, NVIDIA, SiS, and VIA, Intel controls just shy of 90% of the chipset market. Sure, the company derives revenue from this position, but the more important advantage is that whomever controls the chipset market generally has the first and last word on what technologies become widely available in the PC market and is thus in a position to help propel the market forward.

An example might be DDR2 memory. Last year, when DDR and DDR2 were essentially at parity on speed, it was obvious that DDR would soon hit its ceiling for price vs. performance effectiveness. Some in the industry were content to let the market continue investing in a technology that was obviously on a short road to obsolescence. By making DDR2 an essential part of its mainstream and high-end offerings, Intel helped move the market into a forward-looking solution and brought industry DDR2 volumes up to enable price parity with DDR.

What's Hot for Desktop

Scan Intel's current chipset lineup and you'll still see the 845, 865, 875, and 910 families, although the 845 also shows up on the "mature" chipsets list. And sure enough, ASUS still has 865-based boards in production based on Socket 478. MSI still covers the 865 and even has an 848P part. Intel shows two 845-based boards as being current. But this is pretty trailing edge tech destined for the lowest-end configurations. Customers will get Hyper-Threading support, but forget dual-core, SATA, DDR2, or, in the case of the 845 family, anything above a 533 MHz front-side bus.

No, today's action really starts with the 915 family, which introduced DDR2 and PCI Express to the desktop world, although Intel was one of the very few motherboard manufacturers that did not go with the option for DDR memory in its 915-based designs.

Concurrent with the 915, Intel rolled out the 925X chipset, touting memory handling advantages similar to those that separated the 875 from the 865 family. However, if you recall, the "PAT hack" essentially upgraded 865 chips to being 875s. When the 915s arrived, third-party manufacturers made similar modifications, and the end result was that there was virtually no performance difference between the 915 and 925X on benchmarking tests. However, only the 925X offered support for ECC memory and EM64T (IA-32 64-bit extensions), making this a sensible chipset for low-end servers.

Months later, Intel bowed the 925XE, which in all ways was a 925X save for the FSB increase from 800 MHz to 1,066 MHz. This paved the way for modern Extreme Edition chips. The 925XE scored relatively few design wins, no doubt because of the EE processors' high price points, but it was an effective market proof of sorts for the benefits possible with the premium bus speed.

Last summer, the 945 (Lakeport) and 955X (Grantsdale) arrived, marking the debut of dual-core CPU support for consumers and official embracement of 667 MHz DDR2 memory. (Even the 925XE topped out at 533 MHz.) However, this time around, Intel was careful to add some distinguishing features for its higher-end model. While both chipsets supported (in the P and G versions) up to 1,066 MHz on the FSB, only the 955X could run a Pentium Processor Extreme Edition--specifically the model 840 based on the 90 nm fab process. With the 945/955X came the ICH7 southbridge family, which bestowed benefits such as 3 Gbps SATA and a wider selection of RAID options under Matrix Storage as well as NCQ.

Click to see Intel Desktop Board Series Comparison Chart

The 945G integrated the GMA 950 IGP, a marked improvement over the GMA 900. The Intel Memory Pipeline Technology specific to the 955X promised improvements over the 945--and delivered. Better yet for resellers trying to preserve value in the higher-end configuration, no memory hack for the 945 series ever materialized. The memory performance benefits with the 955X weren't vast, but they were noticeable in real-world conditions, and the chip doubled the maximum DDR2 amount from the 945's 4GB to 8GB while keeping the ECC differentiation.

Most recently, the new king of the desktop crop is Intel's 975X. Glance down Intel's charts and you might determine that the 975X and 955X are identical. Not so. It takes a 975X to run the 900-series, 65 nm-based Pentium Processor Extreme Edition chips, which today peaks with the 965--meaning the Extreme Edition 965 processor, not to be confused the forthcoming 965 chipset. Intel refined the 975X's Memory Pipeline Technology beyond that found in the 955X for faster memory bus performance. Latency in the 975X is somewhat lower. More importantly, the 975X finally gives complete support to the x16 PCI Express channel being configured across two PCI Express slots for dual graphics cards support. In fact, the 975X supported ATI CrossFire technology at launch. NVIDIA's SLI is so far not supported.

What's Cool for Mobile

Over on the notebook chipset side, the situation looks similar although less varied. Today's Centrino platform, Napa, is as mainstream as its predecessors. Value SKUs come more from prior generation parts than specially modified versions of the current generation chipset, and there is nothing akin (so far) to the 955X or 975X desktop chipsets that target performance users and overclocking enthusiasts. There is no ECC memory support. Despite increasing sales parity between the desktop and mobile PC worlds, true "ultra-high-end" laptops remain an idea for a future time.

Hunt around and you may still find some original Centrino whitebooks for sale with the 855 chipset. This part provided a 400 MHz FSB, support for up to DDR333 single channel memory, had no TV output, and, depending on the specific model, there were options for discrete AGP 4X graphics and an integrated 32-bit IGP. In all fairness, as a couple of us at Reseller Advocate still use first-gen Centrino notebooks, this remains a perfectly viable solution for budget shoppers aiming to use primarily productivity and Internet applications.

The second-generation 915 (Sonoma) platform bumped the FSB up to a maximum of 533 MHz, added support for dual channel memory up to DDR2 533, gave manufacturers the option of swinging either to SATA or PATA, and added HD Audio to the old AC'97 spec. Importantly, the 915G group's IGP updated to the GMA 900, a far more capable answer than its predecessor, and the entire 915 family adopted support for Intel's new low voltage (LV) and ultra-low voltage (ULV) Pentium M line. This opened the door to ever-lighter and more compact form factors without taking a major hit on performance.

Most recently, the 945GM and 945PM fill out the third Centrino generation, Napa. Most of the innovation here is in the northbridge. The GMA 950 IGP makes another incremental step in 3D performance. Both the DDR2 memory and FSB can now run at a synchronous 667 MHz. The key improvement is dual-core compatibility for the Core Duo processor line, although the Core Solo, Celeron M, and all appropriate low voltage CPUs are also supported. Predictably, the GM part integrates the IGP while the PM does not, although both offer the option for PCI Express x16 discrete graphics as well as four more x1 lanes off the southbridge.

Click to see Desktop Suggestions Platform Matrix

You can see the gap between mobile and desktop narrowing. In fact, given the 533 MHz FSB of the Pentium D 805, one could argue that mainstream mobile is starting to surpass mainstream desktop at some points. Don't forget the architectural advantages present in the Pentium M architecture that were never designed into the Pentium desktop line, which was originally built for power, not efficiency.

Desktop PCs are still a huge business of which Intel owns the lion's share, but the company owns even more in the mobile space, which also enjoys higher margins. Bringing mobile performance as close as possible to desktop level can only benefit Intel and those who resell its products, and the chief way to accomplish this is through the chipset.

Good Sales From Good Logic

Historically, most resellers have treated the chipset as a too-technical distraction. After all, core logic doesn't lend itself very well to being a meaningful line item on a sales sheet. But this is part of why leading with the chipset in the system sales process may be such a smart idea. You won't find a single tier-one OEM taking this approach.

Why lead in with a Pentium D 820 to define a system's functionality? CPUs are easy to upgrade. So are memory, hard drive capacity, and just about every other component in the PC. These specs pitch you into a doller-per-dollar battle against every other PC vendor out there. Educating buyers about chipsets, on the other hand, defines what a PC can become. The discussion revolves around form and function, not arbitrary speeds that will be outmoded in a matter of months or even weeks.

Discuss the competitive advantages of Matrix Storage and HD Audio. Corporate buyers should learn about chipset-enabled functionality such as Intel Active Management Technology, which lets administrators remotely manage networked systems regardless of system state. High-performance buyers need to understand the relationship of the chipset to the CPU from a bus speeds and memory addressing perspective, and if you can throw in tidbits such as how pairing the 955X chipset with an Extreme Edition CPU opens up overclocking options not present on any prior Intel configuration, even better.

Selling the chipset is about selling a solution, not bullet points. Taking this approach can differentiate you from the competition; becoming expert at it might just overclock your sales numbers, too.