This also slows down because it creates more computations
And I do not want to divide my private key into 65536 and search a small amount of each
I want to search only one part
How can I disable it?
i want for ethereum
By not passing --share or -p, and setting both -b and -t to 1 (1 block, and 1 thread respectively), you can completely disable splitting up the range into smaller chunks, but it will make brute forcing slower since you are not utilizing the full hardware of the GPU.
There is no BitCrack for Ethereum AFAIK.