Why isn't RAM as fast as registers/cache memory?

caching memory hardware ram
Andy picture Andy · Sep 23, 2011 · Viewed 9.7k times · Source

Why do we need to cache in Cache Memory? Why cant RAM Memory be made as fast as register or Cache Memory or Cache be as large as RAM Memory (4GB) so that everything can be in cache? Any good article/books to understand these concepts?

Answer

Tom Zych picture Tom Zych · Sep 23, 2011

Faster stuff costs more per bit. So you have a descending chain of storage, from a few registers at one end, through several levels of cache, down to RAM. Each level is bigger and slower than the one before. And all the way at the bottom you have disk.

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