K8T890 Technology

VIA is the first out the block to bring PCI Express to the AMD platform. But there are still some questions on performance and SLI support.


PCI Express acceptance in the enthusiast market has been expectantly slow since Intel’s release of the first boards with the technology back in June.  We say “expectantly” because there were many factors going into the launch that we knew of that would prevent the take of the new bus in any sort of rush.  First, the technology was going to be expensive: new motherboards meant new processors and new video cards and new memory; probably new hard drives as well.  Obviously this meant that processors, motherboards, and memory were uncompetitive to other solutions at the time.  Also, we knew that the availability of these pieces was going to ramp up rather slowly — finding PCIe graphics cards for sale is a recent occurrance and the 775-processors are not quite in abundance.  Lastly, as this was an Intel only release, a lot of the enthusiast and DIY market was just not going to be interested quite yet.

But that is all changing over the course of the next month.  October is going to see the full release of retail motherboards sporting 939-pin processor sockets and PCI Express x16 and x1 slots for the Athlon 64 processors.  While NVIDIA and VIA race with one another to see who can get their products to YOU first, we’ll be here showing you what you can expect from them.

The VIA K8T890 Chipset

In all honesty, the big story here on the K8T890 chipset is PCI Express implementation.  Not much else has changed on the north bridge in terms of performance or features other than that.  VIA’s presentation that they brought to us touches on some interesting points about the market and their chipset, so I am going to go over some of them before we delve into any numbers.

VIA K8T890 - PCI Express Reaches AMD - Chipsets 54

Here VIA talks about an important issue that AMD has been having that they refused to really admit to any of the press.  The upgrade cycle of AMD users has really been in stall mode since the inception of the 939-pin socket.  When users heard about that socket, many held off on their 754-pin purchases to wait for it.  Then, right behind that was the promise of PCI Express on the same 939-pin socket not too long after that, so users were holding off even longer.  Lots of these slides will have marketing-speak in them, like “industry’s most flexible PCI Express core-logic” that we won’t get into here in this technical look at the chipset.

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Some of you may already know about these bandwidth numbers and the reasoning behind Intel’s push for PCI Express acceptance.  There is no denying that the PCI bus was the slowest part of the PC but was responsible for some of the most crucial components: graphics, connectivity and storage. 

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Here is that same argument for PCIe using hard data.  As you can see, the legacy PCI bus was stuck at 133 MB/s in bandwidth while the memory was rocketing past 6.4 GB/s and even the AGP data rates were at 2.1 GB/s. 

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I really like this slide, as it is a great visual representation about what we were saying above about the upgrade cycles on the AMD platforms.  The facts shows that users are hard pressed to spend their dough on any product that looks like its successor is just around the corner; and the PC market is notorious for this.  With 939-pin processors and PCI Express graphics cards always looking like they were right around the corner, quite a few people have been turned off from buying the recently released AMD hardware. 

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VIA’s answer to this delimma is the K8T890 chipset.  It will support the whole range of AMD Athlon 64 processors including the Opteron and Sempron.  I won’t comment on the 90% marketshare claim they make as I don’t know where or how this information was gathered.  You can see here that the chipset supports 20 lanes of PCIe and still supports a PCIe/PCI lock for overclocking.  (It was misnamed the AGP/PCI lock in the slide.) 

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The block diagram for the chipset shows off the PCIe implementation in the north bridge as well as introduces the 8251 south bridge as well.  It supports 4 SATA and 4 PATA drives with RAID support on the SATA side.  It also includes the new VIA 7.1 channel Vinyl Audio support for motherboard manufacturers to implement.  It will also add two additional lanes of PCI Express to the system, making the new total 22 lanes.  

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