19.5 longer wait time than 19.0 PDG cook time
This is the same thing (a box), how can I make the waiting time before hdaprocessor works shorter?

Are you able to attach your scene file/hda? For me, a simple box .hda actually cooks faster in a clean 19.5 install vs 19.0 due to faster hython start-up time -- the same HDA takes ~3.1s to cook in 19.0 and ~1.6s in 19.5.

Note that work items in the HDA Processor node run out of process by default -- this means each work item starts its own hython session that loads the .hda, cooks it, and writes its outputs to disk. Anything that impacts the Houdini's startup time, e.g. loading packages, will also impact work item cook times. You can use Services [www.sidefx.com] to create a pool of pre-started worker processes to avoid that, which is especially useful for light weight HDAs.