: Why are computer CPUs the size they are? Wouldn’t making them bigger give way to more processing power without needing better technology?

Question

Edit : My first post to blow up. Crazy.

In: Technology

Answer 1

For the purpose of a CPU, the signals that matter are 1s and 0s – electric blips or no-blips.

But as long as the 1s and 0s are received and processed, it doesn’t matter if they are “big” or “small”, or carried down large hallways or small corridors.

Let’s say you are carrying boxes that either contain a signal or are empty. On old computers, huge boxes were carried by dumptrucks running down big roads – noisy, inefficient and large.

On new computers, small boxes are carried by small scooters down narrow tunnels. Physically much smaller, requires much less power. But this is great, since the only thing that matters is whether there is a signal in a box or not. You want the pathways and boxes to be as small as possible, as long as they are still received and registered correctly.

What I’m talking about here is really the die shrink process: [https://en.wikipedia.org/wiki/Die_shrink](https://en.wikipedia.org/wiki/Die_shrink) whereby a certain process is just shrunk down in size. This is always a good thing. A huge part of making computers smaller, cooler and faster and being able to be in phones is this shrinking processor.

Another question is making the processors have a bigger volume – at the same time as they shrink internally. Smaller pathways for the signals, just more of them. That’s a more tricky one.

It’s partly that there’s no need to, because the actions of a CPU core, the “instruction set” so to speak, can be performed with a given layout, big or small – so adding more volume to a CPU core has no reason. Instead, as you shrink down the pathways for each core, you add more cores, letting you run more programs at the same time.

CPUs have hence already been made “much bigger” than they used to be, in the sense that they have more cores – if they had as few cores as before, with the pathway shrinkage, they would be even tinier. You can also add things to processor cores, like a form of fast memory (cache) making them run faster, but there’s a limit to how well the improvement scales.

Let’s say that for a CPU to function as a CPU, and perform its instruction set: [https://en.wikipedia.org/wiki/Comparison_of_instruction_set_architectures](https://en.wikipedia.org/wiki/Comparison_of_instruction_set_architectures) it needs to contain a spoon, a fork and a knife, regardless of their sizes. When people write programs, they do so presuming that these are the only tools in the CPU. You get great gains from shrinking the tools inside, but there’s no reason to add more utensils. However, as you shrink them, you get the space to add multiple CPU cores each containing a spoon, a fork and a knife.