Why Cache Memory is needed if we have RAM?

One phrase that PC enthusiasts frequently use is “cache,” also known as “CPU cache.” However, what precisely is it? And for something that sounds so uninteresting, why should you care? Let’s dissect it in a way that is simple to comprehend.
What is CPU cache?
Fundamentally, the CPU cache consists of a tiny, incredibly quick memory located directly within your processor. It functions similarly to a little closet where the CPU can quickly retrieve items without always having to go through your system RAM, which is a much larger bedroom.
There is at least a little amount of cache memory built into every CPU. While high-end CPUs can include numerous gigabytes of cache, lower-end chips may only have a few kilobytes. The powerful Intel Core i9-14900K processor, which was introduced in the previous year, boasts a substantial 36MB of overall cache. Mobile chips also have it; the Snapdragon 8 Gen 3 from Qualcomm has 12MB of L3 cache.
Where is the cache memory located? 
It is often found on the motherboard close to the CPU or on the CPU chip itself. It is situated between the CPU and the main memory. It is connected to the CPU via a separate data channel.
Why do we need cache when we have RAM?
“But I have 32GB of RAM on my mean machine; why do I need this silly cache thing?” you may be asking yourself. Actually, there’s a fascinating backstory to it. Making CPUs faster has always been the goal of CPU designers, whereas RAM manufacturers prioritise packing in greater capacity. As a result, the performance difference between the CPU and RAM grew. And that posed a serious challenge for CPU designers because RAM speed is essential to overall performance in many tasks. They so required a means of bridging that gap.

A core looks In its L1 cache before executing an instruction. A “cache hit” occurs when the data is present, allowing the core to rapidly retrieve and process the necessary information. In the event of a “cache miss,” L2 is searched if the data cannot be located in L1. Still no luck? At that point, the CPU consults the L3 cache. A scenario cache is intended to minimize the need for the core to painstakingly retrieve data from the main system RAM in the event of a catastrophic incident where the data is not present in any level of cache.
Are there any downsides to cache memory?
Just like anything else, cache memory has drawbacks. For the amount of data it can truly hold, it occupies a lot of physical space on the CPU. Its extreme cost is another factor contributing to its limited availability. All things considered, though, it’s a fair trade-off that keeps your system feeling speedy.

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