http://people.engr.ncsu.edu/efg/506/s01/lectures/notes/lec14.pdf
In the preceding two lectures, we have studied coherence and consistency. What’s the difference?
• Coherence assures that values written by one processor are read by other processors.
• However, coherence says nothing about when writes will become visible.
Another way of looking at it:
• Coherence insures that writes to a particular location will be seen in order.
• Consistency insures that writes to different locations will be seen in an order that makes sense, given the source code.
Consistency vs. Coherence