When the target memory block is not in the cache, the write-through policy directly writes the data to memory. In contrast, the write-back policy first loads the data into the cache and then modifies it, which might seem redundant. However, this approach is designed to reduce the number of writes to memory. Although a read operation is added during a cache miss, subsequent writes can all hit the cache. Otherwise, if the data is never read, each write operation under the write-back policy would still need to access the memory.

Translated from: https://juejin.cn/post/7158395475362578462.

My understanding is that it is based on the application of the principle of locality, to reduce the number of writes to memory.

:))