The performance of P102 graphic cards are powerful as the hashing performance can come up to 52-54 Mh/s. This is one of the main reason why promax 7.2 miner is giving 3710 Mh/s.
Initially even i was having certain doubts on the Mh/s but after gathering information i got to know that they are using P102 Graphic cards well there is no doubt on the performance of these cards.