It looks like bittorent version 2 hashes with sha-256 at a 16kb resolution.

pieces root

For non-empty files this is the the root hash of a merkle tree with a branching factor of 2, constructed from 16KiB blocks of the file. The last block may be shorter than 16KiB. The remaining leaf hashes beyond the end of the file required to construct upper layers of the merkle tree are set to zero. As of meta version 2 SHA2-256 is used as digest function for the merkle tree. The hash is stored in its binary form, not as human-readable string.

Seems like that should be easily parallelizable and can fit into thread memory on a modern GPU.

It would just depend on how many 16kb blocks are remaining in that 0.1%

I wonder how viable it would be to bruteforce it. Not a serious proposal but still fun to think about