Write-around is one method for dealing with a block replacement when writing to main memory. That is to say, if the CPU should write to cache, but a different memory block resides in the target location address. With write-around you neatly side-step the issue by just leaving the existing block in the cache and writing the new data to memory.

In other systems, such as a write-through cache or a write-back cache, the block in the cache will be replaced. Write-around may be a good strategy if it is suspected that the cached block is likely to be accessed before the new block.