Computex Half-a-World Away - Part 1: Intel Roadmaps Revealed

Grantsdale & Socket-775

In our review of the 865 line of chipsets we provided a brief introduction to the Canterwood/Springdale successor known as Grantsdale. Grantsdale will accompany the 3.20 - 3.60GHz Socket-775 Prescott CPUs launched in Q2 '04, and will feature the following specs:

- 800MHz FSB support (initially, moving up to 1.06/1.2GHz eventually)
- Dual DDR400/333 SDRAM
- Dual DDR2-400/533 SDRAM (probably reserved for the higher end Grantsdale chipsets, and obviously depending on market availability of DDR2 SDRAM)
- Optional integrated graphics (Grantsdale-G) using a brand new integrated graphics core
- One PCI Express x16 slot for graphics
- ICH6 with support for 4 independent Serial ATA channels and PCI Express x1 slots

The first thing to take away from these specs is that Intel is expecting DDR2 SDRAM to be available in decent enough quantities by Q2 '04 in order to incorporate it into their roadmap. We've seen a clear departure from the RDRAM dominated roadmaps of Intel's past and the trend continues as we look towards 2004.

The presence of Dual DDR2-533 on the roadmap indicates a desired transition to the 1.06GHz FSB, as Intel has been stressing synchronous FSB/memory bus operation for quite some time now. It's interesting that there's no mention of CSA support for Grantsdale chipsets, but it could just be that Grantsdale will be accompanied with an unannounced derivative of CSA. We have little reason to believe that CSA would be changed at all for Grantsdale, it could just be that Intel doesn't see the need to mention the bus much like they don't mention the Hub Link revisions each chipset features (Hub Link connects the MCH/North Bridge to the ICH/South Bridge).

Intel does have a backup strategy, should DDR2 support not be as prevalent as desired, which is to continue to offer DDR support. Luckily, from a bandwidth standpoint, even if Grantsdale launches with no more than DDR400 support, Intel won't pay any performance penalties. The true benefit of enabling DDR2 support is to push for higher speed memory buses beyond 400MHz, which will become necessary as FSB speeds reach 1.06GHz and beyond.

In the unlikely event that DDR2 fails to catch on, Intel could always migrate to quad-channel RDRAM; at PC1066 speeds, a quad-channel RDRAM solution would still be able to deliver as much bandwidth as a 1.06GHz FSB would require at 8.5GB/s. Unfortunately once you move to four 16-bit RDRAM channels, you begin to lose some of the low pincount advantage of RDRAM as a solution - granted that we're still talking about lower pincounts than a 128-bit DDR interface, but the advantage isn't as great anymore. It's interesting how things have changed; at one point, SDR/DDR SDRAM were Intel's fall-back solutions to RDRAM, but now only in the worst case scenario does RDRAM have a place on Intel's memory roadmap.

Graphics will change slightly with Grantsdale; from an integrated standpoint, we'll see the 3rd generation "Extreme Graphics" core in Grantsdale-G. We would assume that Intel would take this opportunity to introduce DX9 class hardware, considering it will be introduced almost two years after ATI put forth their first DX9 GPU. Unfortunately, implementing 24-bit FP pixel pipelines in addition to 32-bit FP vertex pipelines in addition to all of the programmable logic that was missing from the 2nd generation "Extreme Graphics" core would make Grantsdale-G a very large chip.

The high transistor count of a full DX9 part leads us to believe that Intel may favor a partial DX9 implementation ranging from either a core with only partial precision support (16-bit FP precision) or continuing their trend of not including full hardware support in their graphics core. Considering that Longhorn (Microsoft's 3D UI) will include both DX7 and DX9 compatibility modes, Intel could get away with not including a full DX9 implementation in their Extreme Graphics 3 core. Only time will tell but we're not overly confident in Intel doing something incredible with Extreme Graphics 3. Remember that it's in Intel's best interests to place as much stress on owning a fast CPU as possible; offloading work onto a powerful GPU definitely doesn't vibe with their intentions.

The other unique thing about Grantsdale is the introduction of a PCI Express x16 slot instead of an AGP slot for discrete graphics. ATI and NVIDIA have already announced support for PCI Express interfaces on their graphics cards, initially using an AGP-PCI Express bridge, but eventually they will offer native PCI Express cards. We would expect some Grantsdale boards to ship with AGP support as you can't really expect users that buy $500 video cards today to toss them in order to move to Grantsdale.

PCI Express will also be seen on Grantsdale boards in the form of x1 slots, but the usefulness of those slots will be determined by the availability of PCI Express devices.

Finally we see that Intel has increased the number of Serial ATA channels from 2 to 4 with the introduction of a new ICH - ICH6/ICH6R. The Grantsdale chipsets will still feature the same number of USB 2.0 ports as Springdale/Canterwood (8).