Write-Back Cache

What Does Write-Back Cache Mean?

Write-back cache is a caching technique common in most processor architectures since Intel 80486. When required, it copies data to higher level caches, backing store or memory.


Write-back cache is also known as write-behind cache and copy-back cache.

Techopedia Explains Write-Back Cache

Write-back cache is designed to improve or reduce write operations from and to a cache and its data source (RAM, in most cases). It enables control of the time and the frequency at which data is written or copied into the source backing store.

In a write-back operation, any new, requested processor data is written to the cache, but not in the memory. The memory write process is only performed when the cache data needs to be edited or purged for new content.

Write-back cache works in contrast to write-through cache, which simultaneously writes on cache and memory.


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Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.