Introduction

6800 GT top, 6600 GT middle, and 5700 Ultra on bottom

GeForce 6600 GT and X600 XT

Precisely two weeks after its launch at Quakecon, GeForce 6600 GT has arrived! At $200, the GeForce 6600 GT is priced to appeal to the mainstream market. Its NV43 graphics core features eight pixel pipelines with one texture unit per pixel pipe. This 8x1 pipeline configuration was extremely well received with the RADEON 9500 PRO a few years ago. As a GeForce 6 series GPU, the GeForce 6600 GT is fully shader model 3.0 compliant. Shader Model 3.0 adds support for more instructions, dynamic looping/branching, centroid sampling, FP32 precision and more among its list of features. (In fact, NVIDIA claims that GeForce 6600 GT delivers up to eight times the shading power of GeForce FX 5700 Ultra.)

NVIDIA has also carried over the same AA engine and algorithms found in GeForce 6800. This includes NVIDIA’s new rotated-grid sampling pattern for AA, giving GeForce 6600 GT better coverage of the horizontal and vertical dimensions than GeForce FX 5700 Ultra. UltraShadow II has also been integrated into GeForce 6600.

The SLI connector

Samsung 2.0ns GDDR3

All this is wrapped into 146 million transistors. This is 64 million more transistors than GeForce FX 5700 Ultra, and just 14 million shy of ATI’s high-end RADEON X800 series. To help keep the size of the die down, NVIDIA uses TSMC’s 0.11-micron manufacturing process. The use of 0.11-micron allows NVIDIA to incorporate more features into NV43 without needing a larger die, which would make the chip more expensive to produce. When ATI transitioned to 0.11-micron for X300, they claimed that the smaller process provided 40% more transistors per unit area than if they’d used 0.13-micron.

PCI Express 6600 GT card

The 6600 GT is much smaller

NVIDIA clocks the GeForce 6600 GT at 500MHz on the core, and 500MHz for memory. This equates to a fill rate of 4.0 Gigatexels/second, double that of the RADEON 9600 XT and GeForce FX 5700 Ultra, while memory bandwidth peaks at 16GB/sec (an improvement of 1.6GB/sec over GeForce FX 5700 Ultra).

Another comparison shot

Back of the 6600 GT, note the Philips chip on back

In terms of availability, the first boards should begin shipping in mid-to-late September. We’re hoping NVIDIA is able to bump up the release schedule for AGP GeForce 6600 boards. We’ve heard from a few board partners that PCI Express is on tap for GeForce 6600 first, followed by AGP two or three weeks later. Like PCI Express-based GeForce 6800 cards, NVIDIA will focus on OEMs for PCI-E GeForce 6600 at first, with retail to come later. This is because the add-in board market for PCI-E is still quite young; most DIY’ers are still building AGP-based systems.

Unfortunately, we can’t provide performance figures until NVIDIA’s NDA expires next month, but it will be interesting to see how the board fares against RADEON X600 XT. ATI is also rumored to be preparing a challenger to GeForce 6600 that also boasts an 8-pixel pipeline architecture and similar clock speeds, so the mainstream market could be just as competitive as the high-end in a matter of weeks.