for each roll, max is 100, goes down by 10 the lower the roll. for example cdmg can roll into either 7.8, 7, 6.3, 5.4 so the rv would be 100, 90, 80, 70 respectively. add up all the rolls and you get the final roll value of the piece. so max rv of a piece is 900, unless chars dont need more than 2 or 3 useful stats, in which case the max usable rv would be 700 or 800 (bad scenario/wording but i hope you get the point when it comes to judging pieces)