Why does transistor size matter so much for processors?

[TheBiggestOfBuschemis]

What causes the size to matter so much? I know a 7nm CPU is obviously faster than a 14nm CPU, but why is that the case? What's the exact science behind it?

[Guest]

Density. 

You can pack in more transistors per square millimeter. 

 

Not always about "faster" but 7nm is definitely way way more efficient. 

[Electronics Wizardy]

WIth smaller transistors you can have more of them. More transistors allows you to have wider pipelines, more cache, more cores, better memory controller, more specalized instructions.

 

Clock speed really hasen't gone up for a while, pentium 4's were hitting about 4ghz, so its not clock speed.

 

Also smaller transistors let you use less power, and power and cooling is often a limit in designs, so being more efficient allows it to be faster.

[seon123]

29 minutes ago, TheBiggestOfBuschemis said:

I know a 7nm CPU is obviously faster than a 14nm CPU

That's.... Not how it works. The Exynos 9825 used in the Note 10 is not faster than a 9900K. While you can improve performance by moving to a smaller transistor size, this does not always happen. E.g. the 22nm 4790K overclocked and performed better than the newer 14nm 5775C.

[TheBiggestOfBuschemis]

On 1/5/2020 at 3:37 AM, seon123 said:

That's.... Not how it works. The Exynos 9825 used in the Note 10 is not faster than a 9900K. While you can improve performance by moving to a smaller transistor size, this does not always happen. E.g. the 22nm 4790K overclocked and performed better than the newer 14nm 5775C.

Thanks for the insight. Always wondered if the whole smaller transistor equals better performance thing was a myth or not.