Cache Memory Explained: The Biggest Boost to CPU Performance

Cache memory can often bee the single biggest factor in determining the performance of CPU, it is also a large factor in the cost. In this video we explain why. Cache is a small amount of SRAM or other high speed memory between the CPU and Main Memory, it cannot be directly addressed, Every CPU request for memory whether data or instruction is first sent to cache memory controller which is part of the MMU or Memory Management Unit.

We explore locality of reference and how this enables a very small amount of cache memory to handle 95%+ of access requests to memory. We also explore multilevel cache, explaining what L1, L2, L3 and sometimes even L4 cache are and how they work together. We even explain the reason the reason that modern computers are actually Harvard architecture (not strictly von Neumann) because of a separate L1 instruction and data cache.

This video follows a video we created discussion general memory enhancements such as wide path memory access and interleaving. If you have not already seen it you can do so here: https://youtu.be/kg58jDVBmdg

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It is part of my Computer Organization and Architecture course which you can find here: https://www.youtube.com/playlist?list=PL0_aoTs5sGaTt4IuF7jJxqVm4uE-TgsJR

If you have not seen the Little Man Computer (LMC) series of videos, they explore how a computer works at it most fundamental level. You can find them here:
* A recommended introduction to Little Man computer video here: https://youtu.be/4T60r42o9Wo
* A "Hello LMC" video where we do a smaller program and talk more in-depth about the instruction cycle and basic instructions: https://youtu.be/QneVgKf2eVg
* And an intermediate step where we introduce branching and explore recreating conditional statements with LMC: https://youtu.be/fXMCnzdNemc
* Finally we explore iteration, labels and advanced LMC: https://youtu.be/hFg1etP_sFM

Here are presentation slides that can be used as a supplement to follow along and as a future reference for this content: https://drive.google.com/file/d/1htYqGJP3SIizaQf7Ea5yHUREI0kOLdC6/view?usp=sharing