Over the next several days, you'll be hearing a lot about Intel's significant upgrade to the Pentium 4 platform. Soon enough, that brand new Canterwood board you have will be yesterday's news as two new words will be on the lips of all enthusiasts... Grantsdale and Alderwood.

Well, after that dramatic intro, I suppose the real question is what exactly is the Grantsdale and Alderwood all about, and more specifically, why should you the reader care? Despite the drama, the D915P/G and D925X (Grantsdale and Alderwood respectively) really are large jumps in the Pentium 4 platform's history, and offer some serious features that will be impossible to ignore. Since this is a new technology, we'll break this article down in a FAQ format so that it (hopefully) answers any questions you may have.

What are Grantsdale and Alderwood?

Both the D915P/G and D925X are new Express Chipsets designed for the Pentium 4 platform. The chipsets support Intel's HyperThreading technology, Dual Channel DDR2, and PCI Express. They will support wireless access point (WAP) onboard, which Intel claims that along with a wireless card, you can setup a wireless network in four simple steps. I personally doubt this will be secure out of the box, so expect a few more steps than that in order to secure that wireless network.

Intel High Definition Audio, which was something mentioned in our interview with them last month, is a new technology that improves greatly on the onboard audio we were used to before. Of course, RAID is supported by the ICH6R, making the need for 3rd party controllers unnecessary. However, you can expect some of the high end boards to still provide this as an option.

How are they different?

The Grantsdale is geared towards the mainstream/professional user, while the Alderwood is targeted more towards the enthusiast. Though both boards share similar features, there are a few differences that distinguish them from one another. In terms of memory support, the Alderwood only supports DDR2, whereas the Grantsdale will support DDR and DDR2. The Grantsdale will also offer onboard graphics as an option in the form of the 915G.

As you've probably figured out now, this two tier release is similar to the last one we've seen from Intel. Basically, the Springdale market is moving to Grantsdale, and Canterwood to Alderwood.

What is this PCI Express?

The story of the day is going to be PCI Express (PCI-E). Before continuing, let's have a look back at a bit of history.

ISA - Back in the days of single MHz speed PCs, the Industry Standard Architecture (ISA) was the main connection within your PC. Everything from sound cards to video cards went in here. It began as an 8-bit and later expanded to 16-bit, running at whopping speeds between 8 and 10MHz.

Considering the speed of the PCs back then, and their purpose, the ISA standard was fine. Forgotten from this time was the Extended Industry Standard Architecture (EISA) which allowed for 32-bit transfers, but it wasn't any faster than ISA and it was expensive to implement.

VLB - As PC gaming began to take shape, the Video Electronics Standards Association (VESA) introduced the VESA Local Bus (VLB). In simple terms, the VLB was a 32-bit version of the ISA connection and was required for the newer graphics cards at the time. The VLB ran at speeds between 25 and 50MHz.

The VLB ran synchronously with the processor (the 486 at the time), and shared the bus between the VLB and CPU. The problem of course is something similar to what we experience today when the AGP and PCI slots get overclocked. As CPU speeds increased, so did the device plugged into the VLB.

PCI - Version 1 of the Peripheral Component Interconnect (PCI) was first proposed by Intel back in 1991, followed by version 2 a couple years later. It is a 32-bit bus and supports speeds of 33 MHz and 133MB/sec, with later specs allowing 64-bit transfers at 66 MHz. It was the first plug-and-play connection that would automatically configure IRQs and other settings, making the addition of new devices much easier.

Using bus mastering, PCI adapters are able to perform tasks at the same time with the main processor. PCI has the ability to run asynchronously from the processor, so faster CPUs will not put the PCI slots out of spec. Although the PCI bus was separated from the CPU, it did share the bus with other PCI devices. With PC games becoming ever more popular, a change was needed in order to maximize the graphics card's potential.

AGP - The Accelerated Graphics Port (AGP) is exactly what the name implies. Designed by Intel, this connection was based on the 66 MHz PCI specification and runs at 266MB/sec, though modern cards now run 2.1GB/sec. It is a dedicated point-to-point channel, and instead of fighting it out with other PCI slots, the AGP slot has it's own direct link to system memory.

One of the early advantages of AGP was that game textures can be retrieved from system memory, and in theory, video cards would require less memory (making them cheaper) as they did not need to store these textures anymore. I think we know how all that went, but nonetheless, the dedicated high speed connection was required eventually, and the faster connection to system memory does come into play when your video card buffer fills out.

Why the need for PCI Express?

PCI Express is designed to replace PCI and AGP as we know it. There are several advantages to PCI Express but the main thing is to get rid of all the bus traffic we have right now. As it stands, moving graphics to its own AGP slot alleviated the graphics traffic that overloaded the PCI bus. However, hard drive data, networking traffic, sound data, as well as any peripherals plugged into your PC all eat away at the same 133MB/sec the PCI bus allows for. A simple analogy would be as follows:

Imagine the above chart as back in the days of ISA and PCI. You have four lanes of traffic merging into one, hence the bottleneck will occur at the merge. By moving to AGP:

By moving graphics data to it's own AGP, we take away one of the contributors to the PCI bottleneck. However, we can still see there's still a potential traffic jam once data begins to flow.

The above image illustrates the type of flow we can expect from PCI Express. I've simplified it, but basically data will no longer share one path, but rather be split into multiple paths. The standard calls for something similar to dual channel, but in the case of PCI-E, there is a transmit pair and a receive pair. PCI-E speeds will run up to 2.5GB/s with a transfer rate of 200MB/s. For those of you keeping score, that is up to four times faster than PCI.

Costs should be on par, if not lower to replace PCI slots. Since PCI Express is point-to-point, the number of trace routes are drastically reduced. This does not mean PCI will be gone by next week, as there is still an adoption period, but both PCI and PCI Express are capable of coexisting together. At the software level, nothing has really changed, so you should have no problems running a PCI Express system with the current Operating System you're using now. For Intel's launch, expect to see the review boards equipped 16x PCI-E slots instead of 8x AGP slots. Later on, there may be some motherboards where you will have an AGP slot, but this isn't native to the Grantsdale and Alderwood, but rather something like a bridge over the PCI bus.

Did they do something about AC'97?

We already touched upon Intel's High Definition Audio, code named Azalia, but to expand on this, Intel is going to be replacing the dated AC'97 standard we've come to know and not really loved these many years. The High Definition Audio will support 192-kHz quality sound at 32-bits, and offer a number of input/output options, which will depend on the codecs and connections implemented by the motherboard manufacturer.

What's new with their integrated graphics?

Something you'll hear more of is the Intel Graphics Media Accelerator (GMA) 900. This will be replacing the Intel Extreme Graphics 2 we're familiar with on the Springdale. The GMA 900 integrated graphics will be offered on the Grantsdale (915G), and not something you will find on the Alderwood.

Although the GMA 900 won't be competing against the high-end parts from the usual suspects, the onboard graphics will be a DirectX 9 part armed with four pixel pipelines. Pixel Shaders 2.0 will be supported in hardware, whereas Vertex Shader 2.0 in software. OpenGL 1.4 will also be supported. The GMA 900 will also support dual monitors, DVI, and the full range of HDTV via S-Video, composite and component. It will be up to the motherboard manufacturers to make what they feel is needed available, but Intel has left the door open for manufacturers to create HTPC boxes at a fairly low cost when coupled with their High Definition Audio.

What networking standard does their WAP support?

The Intel WAP is another feature intended for ease of setting up a home network (as well as making WAP manufacturers very angry). According to their technical documents, it should be very easy to setup. The WAP will support both 802.11b and 802.11G wireless connectivity via the ICH6RW. Remember that you still need a wireless "B" or "G" card to go along with this to work.

Can I use my current DDR?

DDR2 will be offered on both the 915 and 925, with DDR an option for the 915. In case you're wondering, no, you cannot drop in your current DDR into a DDR2 board. DDR2 has 240 pins, while DDR only has 184 pins, and use the Ball Grid Array (BGA) style of memory as a standard. Most DDR brands should introduce with 400MHz parts, and ramp up as high as 667MHz. On launch, most of the reviews should be using the 533MHz variety of DDR2. All of this speed only consumes 1.8v of power, which is quite a drop from DDR's 2.5v.

Are there any form factor changes for motherboards?

There will not be any changes to start. The first batches of boards you'll see will still be based on the ATX and M-ATX form factor. BTX is on the way though, but I do not think we will see widescale adoption before the end of this year. In the meantime, you should be all right with your current cases and PSUs.

How about the CPUs?

Get used to the terms Socket T and Land Grid Array (LGA), because the good ole Socket 478 is being moved aside as the Pentium 4 matures. The LGA775 will have as the name suggests, 775 pins and the main reason for the move is for electrical engineering and cost.

These CPUs will be based on the Prescott core with the 90nm fabrication process and SSE3. These new CPUs will be launched at speeds up to 3.6GHz, and require a new cooler. The heat issues the Prescott ran into earlier should be addressed with this new change. These processors will all run at 800FSB, and pack in 1MB of L2 cache. There will be an Extreme Edition version at 3.4GHz, and it will sport 512KB of L2, 2MB of L3.

We've discussed it in the forums, but as you've probably noticed, gone are the conventional names such as the "Pentium 4 2.4C". These have been replaced by model numbers, similar to AMD's performance rating. This is to address some of the shopper confusion as clock speed is not always indicative of the system's performance. The clock speeds won't be hidden though, and informed shoppers can still look those up before purchasing.

Final Words

Depending on the chipset, be it the mainstream level 915P/G or 925X, almost every aspect of the consumer market is being targeted with this release. Over the remainder of 2004, you can expect some form factor changes thrown into the mix, but the core features should go unchanged. Intel is throwing a lot of eggs into the basket with the launch of the Grantsdale and Alderwood.

A big push is being made to make your PC the central hub the home entertainment. Items like 8-channel sound, and high definition video won't necessarily force you to toss aside 3rd party products, but depending on your requirements, Intel is doing their best to actually reduce your overall costs in putting a computer together. This may seem like fluff for home enthusiasts, but think of the IT manager. If the audio, video and networking are solid, it will save money (less money to waste on 3rd party peripherals), and save money in the time spent creating disk images and multiple driver CDs. They can consolidate their inventory easier when they have a set platform to deploy.

At this time, Intel is going to have a real fight on their hands until more PCI Express products are readily available. A number of colleagues I have spoken to do not yet have PCI-E video cards, which is cause for some concern since we (as tech site owners) normally have first crack at products. Both ATI and NVIDIA are committed to the PCI-E spec, so it's not like there will be nothing ever, and by the time we see Grantsdale and Alderwood in the retail sector, there should be a fair number of PCI-E products.

Another potential issue is the upcoming BTX standard. BTX will be incompatible with ATX, and you will not be able to migrate your ATX 915/925 to a BTX case and PSU. Again, this won't happen overnight, and I think for those of you who update their systems fairly regularly is not going to have much of an issue with this. The problem is going to be for IT managers who need to plan and forecast their network setups for the next 12 months. Truth be told, even with the prospect of a fully integrated system, I doubt many of them will jump to the 915/925 platform out of the gate, and will likely stick with their current setups until some of the standards stabilize.

Is your current setup going to be obsolete as of today? Despite our intro, I don't think it's all doom and gloom for those of you who just picked up a Prescott and Canterwood this past week. Intel is still committed in supporting past products, and the overall costs at the moment with the Canterwood platform is lower in comparison with the cost of setting up a full blown Alderwood platform.

In six months, it can easily be a different story, as the Socket 478 based CPUs will be very scarce as will the Springdales and Canterwoods you've come to love. By then, we should also see a fair number of reliable products as all the kinks are worked out.

If you have any comments, be sure to hit us up in our forums.

HOME