What is Difference between write back and write through cache?

A caching method wherein modifications to data into the cache aren't copied to the cache source till absolutely needed.

Write-back caching is accessible on many microprocessors, together with all Intel processors as the 80486. With such microprocessors, data modifications to data stored into the L1 cache aren't copied to main memory till absolutely essential.

In contrast, a write-through cache executes all write operations into parallel -- data is written to main memory and the L1 cache concurrently. Write-back caching yields somewhat better performance than write-through caching since this reduces the number of write operations to main memory. Along with this performance enhancement comes a slight risk which data may be lost when the system crashes. A write-back cache is also termed as a copy-back cache.