1 THz processor energy requirements

I refer you to this 9 year old article - "#-Link-Snipped-#"

The article primarily deals with traditional processors and not mobile processors. But the trends and the general message from the article applies also to mobile processors. And the interesting thing is, this trend is still valid..


From the graph, we see that the number of transistors in the processor increases, as expected. That is what the Moore's law says. Ok. But the clock speed, power dissipation and the performance are all stabilizing and not increasing anymore. This is because, the number of transistors doesnt directly translate into performance. Each time you increase the clock speed, you need to increase the voltage level for the processors, and power has a square relationship with the voltage. This means, if you double the clock speed, you quadruple the power consumed. This alone is a big problem, especially in mobile processors.

That is what led to multi-core processors. Let's say you have a processor with 1 MHz clock, and it uses 10 W power. If you increase the clock speed to 2 MHz (which means it's capable of 2 MFLOPS), the power usage will go to 40 W. Instead, if you get another similar processor and connect them together, you just need 20 W power, and you still get 2 MFLOPS performance. This is the basic idea, why multi-core has become very common. It's the way to go, since we cant do much more with single core processors anymore.

So, parallel and concurrent software is how we get more and more performance these days.. Hardware improvements are there, no doubt, but those are not nearly anywhere near wat we used to get in the 90's and 2000's. Today, we just put more cores in a processor and tie together many such processors, and write parallel programs for whatever we want to do.. So, ultimately, even if a 1THz processor is realized at some point in time, it won't be using a single core. It will be a multi-core or many-core processor which has lots of smaller cores with smaller clock speeds.