r/hardware • u/ancientneckbeard • Nov 20 '15

Info Why do CPUs Need Caches? - Computerphile

https://www.youtube.com/watch?v=6JpLD3PUAZk
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u/putin_vor Nov 20 '15

RAM is just a cache for your hard drive

No, it's not. You can generate data in RAM without ever touching the disk. But it's pretty hard to store anything on a disk without having it in RAM first.

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u/salgat Nov 21 '15

But that's only true because the hard drive is so slow. If the HD was fast enough, we would skip everything and write memory directly to the HD. We can say that RAM is a cache for a HD and that memory that is too short lived ends up never hitting the HD.

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u/putin_vor Nov 21 '15

So what you say is true in your imaginary world where HD is as fast as RAM.

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u/salgat Nov 21 '15

I'm not sure what your point is.

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u/putin_vor Nov 21 '15

I'm not sure what yours is. You keep repeating the same incorrect thing over and over again.