NVIDIA's GeForce 8800 (G80): GPUs Re-architected for DirectX 10

The 8800 GTX and GTS

Today we expect to see availability of two cards based on NVIDIA's G80 GPU: the GeForce 8800 GTX and 8800 GTS. Priced at $599 and $449 respectively, the two cards, as usual, differ in clock speeds and processing power.

8800 GTX (top) vs. 7900 GTX (bottom)

The 8800 GTX gets the full G80 implementation of 128 stream processors and 64 texture fetch units. The stream processors are clocked at 1.35GHz with the rest of the GPU running at 575MHz. The GTX has six 64-bit memory controllers operating in tandem, connected to 768MB of GDDR3 memory running at 900MHz. GDDR4 is supported but will be introduced on a later card.

NVIO: Driving a pair of TMDS transmitters near you

You get two dual-link DVI ports driven by NVIDIA's new NVIO chip that handles TMDS and other currently unknown functions. Keeping a TMDS on-die is a very difficult thing to do, especially if you have logic operating at such high clock speeds within the GPU, so with G80 NVIDIA had to move the TMDS off-die and onto this separate chip. The NVIO chip also supports HDCP, but you do need the crypto ROM keys in order to have full HDCP support on the card. That final decision is up to the individual card manufacturers, although at this price point we hope they all choose to include HDCP support.

The 8800 GTX has two PCIe power connectors and two SLI connectors:

Two SLI connectors on the 8800 GTX

Bridges in action

The dual power connectors are necessary to avoid drawing more power from a single connector than the current ATX specification allows for. The dual SLI connectors are for future applications, such as daisy chaining three G80 based GPUs, much like ATI's latest CrossFire offerings.

dual power connectors

The GeForce 8800 GTS loses 32 SPs bringing it down to 96 stream processors and 48 texture fetch units. The shader core runs at 1.2GHz, while the rest of the GTS runs at 500MHz. The GTS also has only five 64-bit memory controllers with 640MB of GDDR3 memory running at 800MHz.

7900 GTX (left) 8800 GTS (middle) 8800 GTX (right)

The 8800 GTS has the same NVIO chip as the 8800 GTX, but the board itself is a bit shorter and it only features one SLI connector and one PCIe power connector.

Only one power connector on an 8800 GTS

...and only one SLI connector

Both cards are extremely quiet during operation and are audibly indiscernible from a 7900 GTX.