system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do CPUs deal with dead transistors?

A CPU has billions of transistors, of which any number of them could be broken or not working - how do they continue functioning without these transistors?
gpt
Welcome to the wonderful world of CPU binning.


Have you ever wondered why Intel doesn't just make i7s? 

This is why.


They try to make all i7s, say a 4 core CPU (not anymore but things have changed a little bit from this a 2 years ago because chiplets).

Say a transistor in 1 core runs a little slow, its not broken but it can't run at full speed. Depending on this speed, they may take this down to a lower tier i7 or an i5.

Say the transistor is completely broke. They will disable that core, disable the second worst core, and call it an i3 with 2 cores.

I do want to note that the vast majority of the transistors aren't transistors in the cores, most of the CPU is cache. In which case they just disable the cache block with the faulty cache, and depending on how much cache they have to disable, they might also disable cores and call it an i3.

In theory these cores disabled beside the faulty cores are perfectly good (though if disabling a working core, they will disable the worst working core), in fact back in the day you could re-enable them and use them, but just to keep a consistent and small set of cpu models they will keep a few of them.

Do note that CPUs don't really have transistors dying with use usually. The only errors are usually in the manufacturing process.

But overall they will only throw away CPUs that don't work completely. Everything else can still be sold.