nncache saves need to query NN for transpositions (increasing nps slightly). Every nncache entry takes 350 bytes of RAM. Every node in the tree takes 250 bytes of RAM. You have to decide yourself whether you want to allow faster search (by increasing nncache) or longer search (by saving RAM by reducing nncache). You can use the formula: max_NN_cache_size = (total_RAM_in_GB)*2500000 - (Longest_move_time_in_minutes)*(nps)*43 22 gbs RAM x 2500000 = 55,000,000 14,000 NPS x 43 = 602,000 60 minutes x 602,000 = 36,120,000 55,000,000 - 36,120,000 = 18,880,000 as max nn cache size. ==== If using a dag build, there's no need to increase max_NN_cache_size past 2,000.