Jabardast aadmi :
At my place gtx 1060 and gtx 980 are similarly priced ,I want this for hardcore gaming and 3d game creation which of the two will be the best
The GTX 980 is better than the 1060 6GB, so it will be even better than the 3GB version of it.
That is at the cost of being more power hungry ( which implies in being hotter as well and requires a stronger PSU) and much older model ( implying in not so good driver support from NVIDIA ).
So, if you're up to those disadvantages the 980 is the best choice, in terms of raw performance.
Otherwise, if you don't mind losing some FPS without having to worrying about nothing else, the 1060 will definitely cut it for you.