Dataset problems

Hi I have a video dataset… I had to change my video frames to small blocks… I changed my frames to blocks in a tensor with this shape([780000,8,8]). some of the blocks are equal. I want to delete the same blocks because this similar blocks have different outputs and my network does not train good…
I used simple two “for” for find similar blocks(I have 780000 blocks (8*8)) but this takes too much time… is there any easier way to find similar blocks 2d blocks in a tensor?