Introduction

In the April 19, 1965 issue of Electronics Magazine Intel co-founder Gordon Moore famously predicted that the complexity of an integrated circuit doubles every two years. This observation later came to be famously known as Moore’s law. While Moore’s law has been tweaked slightly over the years (Moore’s law now states that chip complexity doubles roughly every 18 months), its impact on PC hardware development has been profound. Not only have Intel’s latest CPUs adhered to Moore’s law, it has become a goal that the entire PC hardware industry shoots for.

The key to making Moore’s law possible is the routine shrinking of the transistors that lie within today’s latest chips. As the transistors get smaller, manufacturers are able to incorporate more transistors into the same amount of space and thus increase performance. Think of a transistor as a “feature” – you want 24 pixel shaders instead of 16 or 12? That’s going to cost you more transistors.

If the chip manufacturer wants to reduce the manufacturing cost per chip instead of improving performance, smaller transistors can be used to reduce the overall size of the chip, thus allowing the manufacturer to get more chips per silicon wafer.

Three new cards launching today

The GeForce 7900 GTX and 7900 GT (bottom)

Of course, another important benefit of smaller transistors is that they require less voltage to operate. This in turn generally helps to combat heat assuming a similar chip design is used (to keep things simple, we’re not going to discuss other mitigating factors such as leakage). As a result, manufacturers can (and sometimes will) often crank up the clock speeds to increase performance.

One of the chief reasons NVIDIA grew so quickly to dominate the graphics semiconductor industry in the late 90s and into 2000 (in 2001 NVIDIA was named the fastest semiconductor company to reach $1 billion in revenue) is because they incorporated the latest manufacturing techniques into their products faster than anyone else. NVIDIA became famous for their 6-month product cycles where their products were replaced every six months by something newer and faster. This was previously unheard of in the graphics industry.

With most of their latest GPUs, NVIDIA uses 110 nanometer transistors. While the 110-nm manufacturing process has been very good to NVIDIA and is used in GPUs ranging from the GeForce 6200 TC all the way up to the latest GeForce 7800s, the process is nearly two years old now and doesn’t contain performance-enhancing features like low-k dielectric. Low-k is important, because as the manufacturing process gets smaller the circuits within the chip are crammed closer together. As clock speeds increase, these circuits can begin to interfere with one another. To prevent this from occurring, NVIDIA’s manufacturing partner, TSMC, uses low-k dielectric material on their smaller 90-nm manufacturing process. This low-k dielectric material is used to encapsulate the copper wires from each other, ensuring better performance (and thus, higher clock speeds) and lowering power requirements. Since the 110-nm process was originally intended to be used in value parts, low-k dielectric wasn’t used in order to help reduce manufacturing costs.

The 7900 GT poses with 7800 GT and GeForce 7800 GTX

GeForce 7900 GT reference board

With today’s GeForce 7900 GTX/7900 GT launch, NVIDIA’s moving from TSMC’s larger 110-nm process to 90-nm. But is NVIDIA focusing on improving performance with these new GPUs and the 90-nm process or reducing manufacturing costs? For months now rumors have persisted at sites like the Inquirer that NVIDIA’s latest GPUs would contain more than the 24 pipelines found in the GeForce 7800 GTX. Let’s see what’s new with these GPUs.