NVIDIA's BR02 "High Speed Interconnect" (often abbreviated to "HSI") chip was used in their early PCI Express graphics cards, where it acted as a bridge between the PCI Express connection to the computer and the natively AGP GPU. This allowed NVIDIA to release a PCI Express graphics card without redesigning the graphics card's GPU for the new interface.
NVIDIA has also developed an HSI chip which works in the opposite direction - allowing natively PCI Express graphics card to be released for the AGP interface.