Btpipe vs pipe


I’d like to elaborate the performance difference between the pipes and its block throttled counterparts.

Pipe Transfer: Does the API set a fixed Block size for a pipe transfer or is the size adapted dynamically depending on the transfer length?

Because if the block size is dynamic, I dont understand the statement in the manual, that the Btpipes have better performance when
transferring small buffer sizes.

Or is the process of finding the right block size very time consuming in the case of normal pipes?