system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do modern CPUs have such little cache?

Modern CPUs ( I'll use the 5950x for example) only have around 64mb of L3 cache. Why can't we just put gigabytes worth? I always wondered why they don't just build larger CPUs to fit the cache. Or maybe with the shrinking of components, they could fit larger amounts in the same size chip.
gpt
The point of a local cache is that it have a very low latency. You could have more cache in the CPU but this would probably give a higher latency. Imagine you are drinking lemonade and have a small glass of lemonade and a large mug on the table. You might ask yourself why you just don't drink straight from the mug, why bother with the glass. But that would be quite inconvenient as the jug is quite heavy so you would have to put it down all the time and it would be slower to take a sip of lemonatde. And it is no big incovenience to have to fille up the glass from time to time. It is the same thing with memory cache. The small fast cache is right there next to the CPU cores and responds very fast. If you spend money on a larger cache it would be further away and use more power so it would be slower. And there is not much slowdown in getting the data from the memory into the cache from time to time.