Die size comparison

Both of these chips are large. NVIDIA says the NV40 GPU is 222 million transistors, while ATI says the X800 is roughly 160 million transistors. However, the two companies don't seem to be counting transistors the same way. NVIDIA likes to count up all possible transistors on a chip, while ATI's estimates are more conservative.

Regardless, transistor counts are less important, in reality, than die size, and we can measure that. ATI's chips are manufactured by TSMC on a 0.13-micron, low-k "Black Diamond" process. The use of a low-capacitance dielectric can reduce crosstalk and allow a chip to run at higher speeds with less power consumption. NVIDIA's NV40, meanwhile, is manufactured by IBM on its 0.13-micron fab process, though without the benefit of a low-k dielectric.

The picture on the right should give you some idea of the relative sizes of these two chips. Pictured between them is an Athlon XP "Thoroughbred" processor, also manufactured on a 0.13-micron process. As you can tell, these GPUs are much larger than your run-of-the-mill desktop CPU, and they are more similar in size to one another than the transistor counts would seem to indicate. By my measurements with my highly accurate plastic Garfield ruler (complete with Odie), the ATI R420 chip is 16.25mm by 16mm, or 260mm2. The NV40 is slightly larger at 18mm by 16mm, or 288mm2.

What Garfield is trying to tell us here is that these are not small chips, Jon. The NV40 isn't massively larger than the R420, either, despite the different numbers coming out of the two companies.