The GeForce 6600

Another shot of the 6600 GT reference board

Back of the 6600 GT

One of the features that made ATI’s initial mainstream offering, the RADEON 9500 PRO, such a strong card was its eight pixel pipeline architecture. This gave the RADEON 9500 PRO a fill rate that was quite competitive with the high-end card of the time, the RADEON 9700/9700 PRO. Unfortunately, since the card was essentially a RADEON 9700 in disguise, it was expensive for ATI to produce, and was eventually replaced by the RADEON 9600, which featured half as many pipes.

GeForce 6600

The back of the GeForce 6600

With GeForce 6600, the eight pipe architecture configuration finally makes a return to the mainstream segment, as NVIDIA has chosen an 8x1 configuration for these cards.

Core clock frequency has been increased from 475MHz in GeForce FX 5700 Ultra to 500MHz in the GeForce 6600 GT. This equates to a peak fill rate of 4.0 Gigatexels/second, double that of the RADEON 9600 XT and GeForce FX 5700 Ultra. Meanwhile, the GeForce 6600’s core runs at 300MHz, a figure which is also higher than previous offerings.

Of course, having a fast graphics core like the GeForce 6600 GT means nothing if it’s starving for memory bandwidth. To keep the core fed with data, NVIDIA has paired it with 128MB of GDDR3 memory running at 500MHz (1.0GHz effective).

In order to keep manufacturing costs down, the GeForce 6600’s memory interface is 128-bits wide, just like the GeForce FX 5700 Ultra, but thanks to its high clock speed we’re looking at a peak bandwidth figure of 16GB/sec, an improvement of 1.6GB/sec over GeForce FX 5700 Ultra, but falls well short of the 5900 XT’s 22.4GB/sec. This could give the GeForce FX 5900 XT the edge in some titles under high resolutions, especially with AA/AF enabled. NVIDIA hasn’t determined the final memory clock for the GeForce 6600, but it has been confirmed that it will be outfitted with DDR1 memory.

From a features perspective, the GeForce 6600 GT gives up nothing to its bigger brothers, the GeForce 6800 line. The 6600 is shader model 3.0 compatible, ensuring longevity, and we’ve been told that unlike the GeForce FX 5600 series, NVIDIA hasn’t compromised the AA implementation on the GeForce 6600. The GeForce 6600 borrows the AA engine and algorithms found in GeForce 6800. NVIDIA has also integrated UltraShadow II into GeForce 6600.

So how is NVIDIA able to integrate all this into a card that’s been designed for the mainstream segment? Simple, they shrunk it. The GeForce 6600 is NVIDIA’s first GPU to move to 0.11-micron, manufactured by TSMC. The core itself contains 146 million transistors, 64 million more than GeForce FX 5700, so the move to 0.11-micron was very important for NVIDIA.