That ignores pipelining

Posted Feb 28, 2025 11:50 UTC (Fri) by malmedal (subscriber, #56172)
In reply to: That ignores pipelining by farnz
Parent article: Building an open-source battery

> a signal travelling 2 cm in a typical chip takes about 0.1 nanoseconds to do that (speed of light in a silicon chip is about 2/3rds of that in a vacuum).

The speed you can signal on is governed by the telegraphers equations.

The answer is complicated and depends on the process technology. In 28nm I believe the typical speed of signal propagation is around 20% of light-speed, there are things you can do on the chip to make it faster, at the cost of space and power.

That ignores pipelining

Posted Feb 28, 2025 16:26 UTC (Fri) by malmedal (subscriber, #56172) [Link]

Hmm, I must have remembered a way too high figure.

This article gives a speed of 1200 ps/mm for a 5nm node:

https://semiengineering.com/slower-metal-bogs-down-soc-pe...

speed of light is 3.3ps/mm...