Wich gtx 780 is the best ?!!!!

Solution
It really depends on your needs. They will both pretty much perform the same, the second has slightly higher clock speeds, and what will probably be a quieter more efficient cooler. I have the EVGA 770 with the same cooler design and it works very well. That being said, any gains you get from the higher clock speed can be achieved with overclocks on the first. So the main difference between the 2 will be the cooling design. The first expels the heat from the GPU out of the back of the case, and the second will expel heat inside the case, which won't make a difference if you have good airflow in your case, but if the airflow is in question, the first would be your best option.
It really depends on your needs. They will both pretty much perform the same, the second has slightly higher clock speeds, and what will probably be a quieter more efficient cooler. I have the EVGA 770 with the same cooler design and it works very well. That being said, any gains you get from the higher clock speed can be achieved with overclocks on the first. So the main difference between the 2 will be the cooling design. The first expels the heat from the GPU out of the back of the case, and the second will expel heat inside the case, which won't make a difference if you have good airflow in your case, but if the airflow is in question, the first would be your best option.
 
Solution