system
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human
What is the significance of an 7 nm node and what happens when we can’t go any smaller?

I read that AMD announced a 7nm GPU. What does “7nm architecture” mean and why that over a larger number? Also, what happens when we can’t go any smaller? I heard at one time people thought anything smaller than 10 was impossible.
gpt
The numbers don't really mean much of anything at this point. Nominally, it corresponds to the size of the components the CPU is made of, but it has been basically replaced with marketing wank. 

But you want the transistors as small as possible for a variety of reasons. For one, it makes it easier to fit more of them on the same size chip so you can make a more complex, more capable device. Also, historically, reducing the size of transistors let us decrease the voltage and power so that you can get more computation done with the same amount of energy and also increase the frequency so you can compute faster. That hasn't worked out as well for the last several node shrinks as it tended to for the preceding several decades though.