system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the "silicon lottery"? What makes 2 of the same model of CPUs better/less suited for overclocking?

I'd like to know what makes them behave differently even though they are the same model.
gpt
The silicon chips is manufactured at extremely high precision, on the very limit of what we are able to produce and indeed what is physically possible to produce given the size of the atoms. So sometimes the exact distances between semiconducting elements and the width of traces might varry a bit. This is normal manufacturing defects and can be caused by random vibrations, temperature differences or just the random positioning of individual atoms. But this means that some of the elements like transistors, resistors and diodes might behave differently between dies and differently from each other on the same die.

This is called the sillicon lottery because even if the chips are of the same design and manufactured the same way you do not know how bad the manufacturing defects are until the chip have been made. Manufacturers therefore add tolerances and allow parts of the chip to run at a lower frequency or even shut it off if it turns out the defects are great enough. They can then be sold as cheaper units even though they were manufactured as more expensive units. This process is called binning as each model is a seperate bin that components are put in after their evaluation.

End consumers may also take part in some of this silicon lottery. Sometimes the manufacturer runs out of some of the cheaper models and therefore have to take perfectly good higher quality chips and sell them as the cheaper models. If you get one of these chips you might be able to push it past its expected performance. But even within each model there can be a wide range of possible chip qualities that are just sold as the lowest common denominator. If you are lucky you can get a chip that just bearly failed to qualify as a more expensive model. Especially the most expensive model can have a wide range of quality. A third possibility is that a chip might have failed to certify as an expensive model because it performed worse under higher temperatures. In this case it is possible to get a much better chip by just adding enough cooling instead of the stock cooling option.