With many architectural caches, it's typically valuable to think of miss rate instead. A 5% miss rate is very high if the miss path is 20x the cost of the hit p

With many architectural caches, it's typically valuable to think of miss rate instead. A 5% miss rate is very high if the miss path is 20x the cost of the hit path - misses account for 1/2 of the execution time, so reducing that to 4% gives a 10% improvement in runtime.