The new Komodo Dragon 3 engine has gained 100 Elo points in playing strength over its predecessor when using a processor core in blitz. That's a huge improvement for a program that already reached at an Elo level of over 3500!
The gain is even greater (120 to 130 Elo points) for unbalanced openings, e.g. rare variations or gambits. On multiple cores or longer time controls the Elo gain can be somewhat smaller, due to the higher draw range.