Agp Bridge?????

[sigmaseven]

The main debate about PCI Express at the moment is between Nvidia and ATI. ATI are implementing there cards with a true native PCI express connection. On the other hand Nvidia are implementing there current technology with an AGP Bridge, to convert PCI Express to AGP signals. This bridge chip is called the High Speed Interconnect (HSI) chip. Its a fully reversible chip will allows AGP GPU's to be run on PCI Express interfaces, and could be utilized to allow the use of PCI Express GPU's on an AGP bus.

As this chip is on the graphics card itself there is no wasted bandwidth on the motherboard, you still get the full bandwidth from the memory to the graphics card. To carry this bandwidth all the way through Nvidia has cranked up the speed of the AGP speed on the card itself to AGP16x. You now have no bandwidth loss. ATI claim the loss is involved with latencies when using a bridge chip during the translation. Now for a reality check. The step up from AGP 4x to 8x did very little for the graphics industry in its current state. 3D games today were not fully utilizing the available bandwidth in AGP 4x. The step up to AGP 8x only allowed for improvement in extreme circumstances anyway. This is not to say that this will always be the case. But my stance on this is by the time you need to the full 16 channels of PCI express Nvidia will be using native PCI Express cards in a whole new generation of graphics technology


Is this true? So all nvidia new pci express cards work with agp too? And if the bridge is an add on, is the bridge free with the card? Or do you have to buy it?

[sigmaseven]

bump bump bump bump

[Alaron]

The AGP bridge is not a physical peice of silicon but a chip that is built into the card. Meaning that ATI built its cards with a a new chip that takes advantage of the PCI-Express system. NVIDIA, on the other hand chose not to implement the technology straight off, and went with an easier route but simply creating this bridge chip to convert the pci-express signal from the mobo into the AGP signal that the video card uses on its GPU.

PCI-Express is a different slot all together from AGP. You cannot put an AGP card into a PCI-E slot or vice-versa.

So, since this bridge they are talking about is not an actual little card, don't worry about it. You won't buy it, its a part of the card.
You can see the chip on a video card here: http://graphics.tomshardware.com/graphic/20040310/pcie-07.html

And don't worry about performance either. Just like AGP 8x is not used to its full extent, it will be a long time before the full bandwidth of PCI-E will be needed.