Original Link: http://www.anandtech.com/show/1512



VIA Chipset Roadmap

Competition drives our industry, and so we are always glad to see alternatives for various computer components from more companies. Anyone who has followed computers for a reasonable amount of time will have had good experiences and bad experiences with products from every company, and so regardless of past experiences, we always look to future products with a ray of hope. Only final hardware and testing will truly tell whether a design is brilliant in all aspects or if it has flaws that need to be addressed.

VIA has had some great chipsets in the past - for a while they were really the only viable alternative to Intel chipsets. The early Pentium 4 chipsets from VIA faced legal concerns as well as performance problems, and so adoption by motherboard manufacturers was rather slow, but that does not seem to be a problem anymore. On the AMD front, VIA was arguably the better chipset at the time the Opteron and Athlon 64 launched and NVIDIA had to play catch-up, but catch-up they did. Performance between the K8T800 Pro and Nforce3 250 Ultra is very close, but NVIDIA offers additional features and improved overclocking. As we shift towards support for newer technologies like PCIe we will have to see who comes out on top.

VIA is one of the few companies that has a complete chipset portfolio for both AMD and Intel platforms, not to mention their own CPU and graphics chips - more on those in a moment. What this means is that they continue to produce chipsets both with and without integrated graphics for each platform, with multiple chipsets in each category. Their latest roadmap includes their chips that have recently started shipping as well as updates planned for the next few months. We'll provide a quick overview of all of these options, starting with their Intel parts.



VIA Socket 478/775 North Bridges

VIA has Pentium 4 chipsets both with and without integrated graphics. Features vary a little, with the discreet parts generally being more performance/enthusiast oriented. Here is the list of current and upcoming discreet chipsets.


Platform Summary - Discrete P4 Chipsets
PT880 Pro PT894 PT894 Pro
Processor Bus 533/800/1066MHz 533/800/1066MHz 533/800/1066MHz
Memory Support Dual Channel DDR-1 333/400 & DDR-2 400/533/667 Dual Channel DDR-1 333/400 & DDR-2 400/533/667 Dual Channel DDR-1 333/400 & DDR-2 400/533/667
Graphics Support Universal Graphics Interface: PCI Express and AGP 3.0 PCI Express VIA DualGFX Express (Dual PCI Express)
Chip Interconnect Ultra V-Link Ultra V-Link Ultra V-Link
South Bridge VT8237 VT8237/VT8251 VT8251
Sampling Oct. '04 Now (Sept. '04) Oct. '04

As you can see, all of the designs are very similar in terms of features. The key difference is in their south bridge and graphics support. First, let's talk about the graphics. The PT880 Pro will be one of the few options for motherboard manufacturers looking to include fully functional PCI Express and AGP graphics interfaces. We have heard of a bridged PCI-to-AGP connection being offered by some manufacturers, but the VIA chipset should provide full AGP compatibility without a bridge. This may be the only real performance option for those looking to migrate gradually from AGP to PCI Express.

On the high end, dual PCIe graphics interfaces will be an option with the PT894 Pro chipset - each will run as a PCIe X8 connection, but they will be X16 slots. As we have yet to tap the full potential of AGP 8X bandwidths, this should not present a problem. As far as the South Bridge features, we'll cover that in more detail in a moment, but the PT880 Pro is limited to the VT8527 South Bridge while the PT894 Pro is requires the VT8251 South Bridge, and the PT894 can support either one. The VT8251 is a more advanced - and expensive - option, so the PT894 Pro will be targeting the enthusiast market.

You can also see that, similar to Intel's i915P chipset, all of the VIA chipsets will allow for the use of either DDR or DDR2 memory; although the use is exclusive so you will not be able to use both DDR and DDR2 at the same time. VIA also offers the PT800 and PT880 - and several other older chipsets. They are more or less like the PT880 without PCI Express or DDR2 support, and the PT800 features a slower chipset interconnect. VIA uses their proprietary V-Link design for the chipset interconnect on all of their current chipsets. The link runs at 533 MHz and uses either an 8-bit (8X V-Link) or 16-bit (Ultra V-Link) bus. This provides for 533 MB/s or 1066 MB/s of bandwidth, respectively, which is more than enough for the current demands of South Bridge devices.


Platform Summary - Integrated P4 Chipsets
P4M800 P4M800 Pro PM880 PM890
Processor Bus 400/533/800MHz 400/533/800MHz 400/533/800MHz 400/533/800MHz
Memory Support Dual Channel DDR-1 333/400 & DDR-2 400/533/667 Dual Channel DDR-1 333/400 & DDR-2 400/533/667 Dual Channel DDR-1 333/400 & DDR-2 400/533/667 Dual Channel DDR-1 333/400 & DDR-2 400/533/667
Internal Graphics UniChrome 200 MHz UniChrome Pro 200 MHz UniChrome Pro 250 MHz DeltaChrome IGP (DX9)
External Graphics AGP 4X/8X AGP 4X/8X AGP 4X/8X PCI Express
Chip Interconnect 8X V-Link 8X V-Link Ultra V-Link Ultra V-Link
South Bridge VT8237 VT8237 VT8237/VT8251 VT8251
Sampling Now Nov. '04 Already Available Q1'05

Moving on to the Integrated Graphics chipsets, we have four options. The PM800 and PM880 are already available and only provide support for DDR RAM, with the PM880 offering a faster interconnect and support for the VT8251 South Bridge. They both feature S3 UniChrome Pro integrated graphics, although there may be a difference in the clock speed of the IGP. The only additional feature of the PM800 Pro appears to be DDR2 400/533 support; the additional bandwidth that DDR2-533 offers should improve the performance of the IGP somewhat. At the top of the IGP chipsets we have the PM890. It uses the DX9 capable DeltaChrome IGP and provides support for an add-in PCIe graphics card as well as DDR2-400/533/667 memory. As with the PT894 Pro, it only supports the more advanced South Bridge and will geared more towards the enthusiasts. Performance of the DeltaChrome IGP is not likely to come anywhere near the level of a discreet NVIDIA or ATI graphics card, but it should compare favorably with the Intel GMA900. Driver support for the integrated graphics is always a big concern, and we can only hope that it will be better than what we have seen in the past.



VIA Socket 754/939/940 North Bridges

VIA's AMD chipset offerings are pretty similar in terms of features to their Intel offerings. Let's start with the discreet solutions again.


Platform Summary - Discrete Socket 754/939/940 Chipsets
K8T800 Pro K8T890 K8T890 Pro
Processor Bus 1 GHz HyperTransport (1 GHz 16-bit Full Duplex) 1 GHz HyperTransport (1 GHz 16-bit Full Duplex) 1 GHz HyperTransport (1 GHz 16-bit Full Duplex)
Memory Support Single- or Dual-channel DDR-1 266/333/400 Single- or Dual-channel DDR-1 266/333/400 Single- or Dual-channel DDR-1 266/333/400
Graphics Support AGP 4X/8X PCI Express VIA DualGFX Express (Dual PCI Express)
Chip Interconnect 8X V-Link Ultra V-Link Ultra V-Link
South Bridge VT8237 VT8237/VT8251 VT8251
Sampling Already Available Now Now (Sept. '04)

As you can see, things match up almost exactly with the Intel platform chipsets. Of course they use a HyperTransport bus to interface with the processor as opposed to the quad-pumped bus of Intel designs, and they do not have a memory controller as that is taken care of by the AMD processors. Other than that, though, we see similar features with the difference being in the graphics and South Bridge support. VIA does not have plans for an AMD chipset with both AGP and PCIe interfaces, but we still have the option of a dual PCI Express graphics solution with the K8T890 Pro. Again, the high end model requires the use of the more advanced VT8251 South Bridge, but those are the only major differences. Remember that DDR2 memory support is not an option for AMD systems right now, as that is determined by the CPU's memory controller.


Platform Summary - Integrated Socket 754/939/940 Chipsets
K8M800 K8M890
Processor Bus 800 MHz HyperTransport (800 MHz 16-bit Full Duplex) 1 GHz HyperTransport (1 GHz 16-bit Full Duplex)
Memory Support Single- or Dual-channel DDR-1 266/333/400 Single- or Dual-channel DDR-1 266/333/400
Internal Graphics 200 MHz UniChrome Pro 250 MHz DeltaChrome IGP (DX9)
External Graphics AGP 4X/8X PCI Express
Chip Interconnect 8X V-Link Ultra V-Link
South Bridge VT8237 VT8251
Sampling Already Available Oct. '04

On the integrated graphics chipsets, we have only two options. The currently shipping K8M800 uses the older UniChrome Pro IGP with the option of an AGP add-in card, while the K8M890 includes the DeltaChrome IGP as well as a PCI Express graphics slot. The K8M890 also supports a faster 1 GHz HyperTransport bus and the Ultra V-Link. As there are currently no high performance IGP chipsets for Athlon 64/Opteron, VIA has the potential to gain some market share, especially in the low-cost market. Of course, our recent look at ATI's chipset plans show that this is not going to be the case for much longer. Depending on pricing, though, VIA may still provide a reasonable alternative to other IGP solutions.



VIA South Bridges

Finally, we come to VIA's South Bridge offerings. Due to the proprietary V-Link interconnect, VIA's South Bridges can only be used with VIA's North Bridges and vice versa, but that is nothing new or unusual. Let's take a look at the options.


Summary - VIA South Bridges
VT8235 VT8237 VT8251
IDE 2 Channel ATA 33/66/100/133 2 Channel ATA 33/66/100/133 2 Channel ATA 33/66/100/133
Serial ATA N/A 2 SATA 4 SATA with Command Queueing
PCI Express N/A N/A 2 PCIe lanes
RAID N/A 0/1/0+1/JBOD 0/1/0+1/JBOD
Chip Interconnect 8X V-Link Ultra V-Link Ultra V-Link
Network 10/100 MAC 10/100 MAC 10/100 MAC
PCI 6 PCI Slots 6 PCI Slots 7 PCI Slots
Audio 6 Channel Audio 6 Channel Audio High Definition Audio 192K/32-bit 8 Channel
Sampling Already Available Already Available Now

The VT8235 is a slightly older South Bridge, as you can see by its lack of support for SATA and RAID. It is still in use on many socket A and earlier P4 motherboards, though, as well as in embedded systems that use VIA's low-power, low-cost C3 processor. (We won't bother with the details on VIA's socket 370 of socket A chipsets as those have both been available for some time now.) These days, the VT8235 is a low-cost, no-frills South Bridge that goes into budget systems as well as embedded devices.

VIA's VT8237 South Bridge is the updated version of the VT8235 and it adds the "missing" support for up to 2 SATA devices and basic RAID. Depending on the North Bridge on the motherboard, the VT8237 can use the Ultra V-Link connection or the older 8X V-Link. Performance with RAID and Gigabit Ethernet may benefit slightly with the faster V-Link, although generally the 533 MB/s transfer rate of the 8X V-Link should be more than sufficient. Both the 8235 and 8237 can be paired with either a standard AC'97 codec or the enhanced 24-bit VIA Envy chip and codec. VIA Envy is a good quality audio solution that is used on several add-in cards, but unfortunately not many motherboard manufacturers are willing to include it as it increases costs slightly.

The third South Bridge VIA offers is their new VT8251. It is a substantial upgrade in features from the others, as it includes not only RAID and SATA support - this time with native support for 4 SATA drives - but it also adds in some other goodies. For starters, the SATA controller now supports Native Command Queuing. There are also two PCIe lanes, allowing either two X1 PCIe connections or one X2 PCIe connection. Here, the faster Ultra V-Link will definitely help out. On the audio side, the VT8251 adds support for 8 channel High Definition Audio (192 KHz/32-bit sampling). AC'97 audio is still supported as well, as is VIA's Envy 24-bit audio chip. Finally, the ACPI controller is 2.0 compliant, which allows for additional power saving features.

Closing Thoughts

In addition to all of their North and South Bridges, VIA also manufactures a wide variety of companion chips to add additional features to any motherboards. These chips can be used in boards both with and without VIA chipsets. There are no new additions to their companion chips, but just to provide a quick overview, the following technologies are covered. Networking in both 10/100 and GbE options, IEEE1394/Firewire, SATA, PATA, USB2.0, Audio, TV Out, and DVI connections. Chances are pretty good that if there is a technology that is used in computers, VIA makes a chip that supports it.

So, that's what VIA has in plan for the near future as far as chipsets go. We look forward to testing out products using these chips in the future, and we'll be sure to keep you posted on availability and performance. We should hopefully see some competition for Intel in the PCI Express chipset arena before the end of 2004, and competition is good.

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