The stacks are from a midrange canon eos, exported from lightroom, 18MP photopro tif (I tried 24bpp & 48bpp, compressed and uncompressed), each of the 20 folder contains ~30 images.

I've had another systematic look at it, and here's the result: The problem simply seems to be that the more stacks ...

I discovered that queueing works ok when I manually load an image batch and then add it, while it slows to a crawl when adding folders or subfolders...

I am currently re-evaluating hf (latest build) because my eos 60d now works w/ remote. I am on a box that has to be considered rather low-end (core i3, 4gb, win7-64), thus I am trying to queue my 18mp tif stacks and let them be process overnight. However, I am not exactly successful at doing that ...