The CPU must deliver its data at a very high speed. The regular RAM can not keep up with that speed. Therefore, a special RAM type called cache is used as a buffer - temporary storage. To get top performance from the CPU, the number of outgoing transactions must be minimized. The more data transmissions, which can be contained inside the CPU, the better the performance. Therefore,the 486 was equipped with a built in mathematical co-processor, floating point unit and 8 KB L1-cache RAM. These two features help minimize the data flow in and out of the CPU.
Cache RAM becomes especially important in clock doubled CPU's, where internal clock frequency is much higher than external. Then the cache RAM enhances the "horsepower" of the CPU, by allowing faster receipt or delivery of data. Beginning with 486 processors, two layers of cache are employed. The fastest cache RAM is inside the CPU. It is called L1 cache. The next layer is the L2 cache, which are small SRAM chips on the system board. See at the illustration below:
Cache RAM becomes especially important in clock doubled CPU's, where internal clock frequency is much higher than external. Then the cache RAM enhances the "horsepower" of the CPU, by allowing faster receipt or delivery of data. Beginning with 486 processors, two layers of cache are employed. The fastest cache RAM is inside the CPU. It is called L1 cache. The next layer is the L2 cache, which are small SRAM chips on the system board. See at the illustration below:
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