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Slow Response Time



  • Brian Lawson Community moderator
    • Which year Retina 5K are you running and how much RAM does it have?
    • How much free disk space do you have?
    • Define 'significant'


  • Mike Bruce

    27" Retina (3.2 GHz Quad-Core Intel Core i5)

    24 GB RAM (1867 MHz DDR3)

    69 GB free disk space

    "significant" = 1/2 - 3/4 sec to process the moved slide

  • Brian Lawson Community moderator

    I need to know exactly which iMac Retina 5K you have. There are 6 different models that match that description made between 2014 and 2020. What year model is it please?

    Which sliders are you using that are showing the lag? How much processing have you done on the file? What kind of edits have you performed before the lag starts showing up or is it doing this right out of the gate?

    What kind of file are you working with and how large is it?

    How do you have Photo RAW's (I'm assuming this is the program we are talking about? Which version are you running?) Preferences > System settings set? You can see mine in the screenshot below.

    You can try lowering the Video Card Strength and turn on the option Fast Preview. This will reduce the quality of the image rendering while you are making your adjustments then return to full quality when you've finished.

  • Mike Bruce

    Late 2015

    Contrast / Exposure / Highlights / Shadows ...

    Canon CR2

    Photo RAW 2022 (just downloaded today)

    I am messing with the Preferences / System now.  My cache shows 5000, but the slider bar is to the far left and it cannot be moved.  I can type into the numerical window however.

  • Brian Lawson Community moderator

    That year's iMac came with options for 4 different GPUs. Some have only 2GB of VRAM while the others have 4GB. Do you know which one you've got? About this Mac should tell you.

    If you've got the 2GB VRAM version that is going to impact the program's performance.

    The Cache Size will not affect the program's performance while editing. It deals with previews in the Browser. See Catalogs and Caches - ON1 Photo RAW 2022 & ON1 PHOTO RAW 2021 for more info on that aspect of the program. You might want to read it more than once. It took me a couple of readings to get my head around everything. Still, you should be able to move that slider without any problems.

    You might have noticed that my Scratch Folder and PerfectBrowseCache are not at the default location which is inside your user account's Application Support folder on the boot drive. I've added a fast SSD dedicated to just those items. This will improve the program's performance as well as removing the PBC space requirements from the boot drive. The PBC will grow to be as large as needed (see the link above for details) to hold all the previews for your images. On systems with smaller boot drives this can be a significant hit to the system. Also, by moving those items to their own drive you remove any I/O contention that can slow the program's performance when it needs to access either of them. I highly recommend adding a dedicated SSD for them.


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