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→What is a Cache?
So why do we have so many types?
In an ideal world, the CPU would have lightning-fast access to all data on your machine at any given time to maximize the power and speed of modern-day CPUs. In reality, there are limitations and trade-offs when balancing speed, storage sizecapacity, location, and cost. To compromise, a computer utilizes many types of memory. To name the important ones in the hierarchy, we have secondary memory like hard drives and SSDs which can permanently hold vast quantities of data but are slow. Next is Dynamic Random Access Memory(DRAM) which is much smaller, faster, and volatile. Last, we have the cache or Static Random Access Memory(SRAM), which is extremely fast, but even smaller and more expensive.
If the CPU solely relied on getting data from secondary memory, the slow access speed of the storage device would become a massive bottleneck in computation time. There would be huge gaps of time where the CPU sits around doing nothing waiting for data. To the end user, your machine would appear to be extremely sluggish and non-responsive.
