As per my experience due to what the ASICs tend to do and presuming SHA256 is everything it claims to be.
Actually they are not generic hashing chips and any sort of quickly hashing every file is not applicable.
They couldn't even do a single SHA256 hashing of a few bytes, as the hash isn't actually returned.
The output of a SHA256 hashing is supposed to be sufficiently unpredictable that any task you think you could accelerate by exploiting what the ASICs do and working back from there is also not going to fly.