(07-07-2019, 09:00 PM)pistikem Wrote: thank you, rich2005.  there may be something broken in my Gimp version or in the environment it runs in on my Slackware box : it usually uses 2 cores - but then when i play a bit in the Color to Gray GUI window, for example with 'split window' or even just pressing 'cancel', Gimp suddenly makes use of all cores for quite a while till the end (24 Mpxls), or interrupts this and goes back to the 2-core speed.  i monitor this with xosview or with nmon.  it's quite erratic and is annoying as i have a workflow in which i want to keep processing times as short as possible...