Native vs. Bridged PCI Express

Long before the appearance of PCI Express-supporting chipsets, ATI and NVIDIA announced their new products intended for the upcoming platforms. Both companies just added support of the new interface to their existing architectures, but ATI did it on the chip level, while NVIDIA introduced a special AGP ?PCI Express converter for its GeForce 4, FX and 6 series chips.

ATI Technologies put an emphasis on the “native?support of PCI Express by its chips, winning close to 100 percent of the PCI Express graphics market with major OEMs, while NVIDIA was talking about a bright future when its PCI Express chips would work on AGP-interfaced graphics cards thanks to the same HSI bridge, making NVIDIA popular among people who upgrade their PCs often.

Both companies proved right in their own ways: ATI is currently developing its own PCI Express-to-AGP bridge, while NVIDIA ships GPUs with native support of PCI Express. From the economical standpoint, however, ATI’s approach was more realistic as the huge share of the PCI Express market the company owns now is a confirmation of.

NVIDIA SLI: Luxurious Tech for All?

The PCI Express variant of the GeForce 6800 got one more thrilling innovation, the support of the SLI technology. Read more about this technology in our article called NVIDIA SLI: Sometimes They Come Back...

3dfx, once the leader of the graphics market, used the SLI abbreviation to denote a technology that allowed for two graphics processors to work in pair. Now NVIDIA, who devoured 3dfx a few years ago by the way, revives the concept. NVIDIA’s SLI technology allows to install two GeForce 6800 PCI Express graphics cards into one system and to achieve a higher graphics performance. The only prerequisite is the availability of two PCI Express x16 slots on the mainboard, and a special connector on each of the graphics cards.

In spite of much clamor and promises to ship SLI systems by the end of the summer or beginning of the fall, first PCs with two graphics cards became available only in November, priced at $5000-6000. NVIDIA, however, says the SLI technology can be employed in rather inexpensive PCs ?everything is already built into the nForce4 SLI chipset and the GeForce 6600 GT graphics processor.

While other chipset makers are preparing their chipsets that would provide two PCI Express x16 slots (maybe reduced to x8, for example, in the number of PCI Express lanes) and ATI is going to unveil its own vision of multi-processor graphics solutions soon, mass shipments of NVIDIA’s SLI haven’t yet begun, and such solutions ?for $5000 in the realization of Alienware and VoodooPC ?are rather a piece of luxury than a typical computer.

Now we will only see in the year 2005 if the SLI technology can really become an affordable option.