Write buffer

A write buffer is a type of data buffer.

In a CPU cache, a write buffer can be used to hold data being written back from the cache to main memory. This is a variation of write-through caching called buffered write-through.

Use of a write buffer in this manner frees the cache to service read requests while the write is taking place. There is usually only one stage of buffering, so subsequent writes must wait until the first write is complete. Since most accesses are reads, buffered write-through is typically only useful for very slow main memory.