GeForce 6 Series - GeForce 6800 Series

GeForce 6800 Series

The first family in the GeForce 6 product-line, the 6800 series catered to the high-performance gaming market. As the very first GeForce 6 model, the 16 pixel pipeline GeForce 6800 Ultra (NV40) was 2 to 2.5 times faster than Nvidia's previous top-line product (the GeForce FX 5950 Ultra), packed four times the number of pixel pipelines, twice the number of texture units and added a much improved pixel-shader architecture. Yet, the 6800 Ultra was fabricated on the same (IBM) 130 nanometer process node as the FX 5950, and it consumed slightly less power.

Early benchmarks put the 6800 series at a disadvantage when compared to similarly priced ATI cards. Newer drivers have improved performance on both companies' products. Against the ATI's Radeon X800XT PE, its direct competitor, the 6800 Ultra performed comparably in most synthetic and game benchmarks, with each card showing its individual strengths in different gaming applications. Nvidia's part is strong in many applications programmed for OpenGL (a traditional strength of Nvidia), while ATI leads in many Direct3D applications. Thus, it is now generally accepted that the GeForce 6800 Ultra is similar in performance to the Radeon X800 XT, and that the GeForce 6800 GT generally performs better than the Radeon X800 Pro.

Like all of Nvidia's GPUs up until 2004, initial 6800 members were designed for the AGP bus. Nvidia added support for the PCI Express (PCIe) bus in later GeForce 6 products, usually by use of an AGP-PCIe bridge chip. In the case of the 6800 GT and 6800 Ultra, Nvidia developed a variant of the NV40 chip called the NV45. The NV45 shares the same die core as the NV40, but embeds an AGP-PCIe bridge on the chip's package. (Internally, the NV45 is an AGP NV40 with added bus-translation logic, to permit interfacing with a PCIe motherboard. Externally, the NV45 is a single chip with two separate silicon dies clearly visible on the top.) NV48 is NV45 with 512MB RAM.

The use of an AGP-PCIe bridge chip initially led to fears that natively-AGP GPUs would not be able to take advantage of the additional bandwidth offered by PCIe and would therefore be at a disadvantage relative to native PCIe chips. However, benchmarking reveals that even AGP 4x is fast enough that most contemporary games do not improve significantly in performance when switched to AGP 8x, rendering the further bandwidth increase provided by PCIe largely superfluous. Additionally, Nvidia's on-board implementations of AGP are clocked at AGP 12x or 16x, providing bandwidth comparable to PCIe for the rare situations when this bandwidth is actually necessary.

The use of a bridge chip allowed Nvidia to release a full complement of PCIe graphics cards without having to redesign them for the PCIe interface. Later, when Nvidia's GPUs were designed to use PCIe natively, the bidirectional bridge chip allowed them to be used in AGP cards. ATI, initially a critic of the bridge chip, eventually designed a similar mechanism for their own cards.

Nvidia's professional Quadro line contains members drawn from the 6800 series: Quadro FX 4000 (AGP) and the Quadro FX 3400, 4400 and 4400g (both PCI Express). The 6800 series was also incorporated into laptops with the GeForce Go 6800 and Go 6800 Ultra GPUs.

As of August 2010, NVIDIA and Adobe Flash 10.1 does not provide GPU acceleration for GeForce 6 series as a result HD Video playback through Adobe Flash may suffer from digital artifacts, or extreme video lag on Pentium 4 2.8 GHz or slower systems.