EDIT: I rewrote this post, i've managed to work it! now i have a zobrist hashing and the speed gain is very nice. thanks a lot Alvaro for the help
But i have a another question related to the transposition table management. would you recommend using some sort of replacement scheme for same positions with different depth? say if the new position has a larger depth than the saved one than i should replace it with the new one. casue right now i am not doing any replacement,i am just inserting the positions blindly to the table.
I am handling collisions by using a LinkedList in every table index,so if two board positions fall at the same index, i just add them to the list.
And what size of Transposition table do you recommend using? right now i have table at size 500009 . but when i measure the amount of insertions to the table,I get more than 3 million ! (depth 15)