Skip to main content
graphics_4075
graphics_4075
Inspiring
August 10, 2026

Harmonize layer mask is incredibly slow

  • August 10, 2026
  • 2 replies
  • 42 views

Mac Studio M1 Ultra, Tahoe 26.5.1

Photoshop 27.9.0

 

I have been testing the new Harmonize feature a bunch, and all other quirks it has aside, it is near impossible for me to adjust the masks that it produces. I am not sure what is causing this (Gen-AI is my guess..) but I would describe it as an input-lag. If I am trying to manually adjust the mask with the brush tool, I am met with such a delay that I am unable to do anything precise. 

 

The Harmonize feature seems to function at a normal speed, it it just customizing the mask that it produces that lags.

 

I would not imagine my hardware matters here since nearly every other Photoshop feature runs pretty quickly and the M1 Ultra chip is still quite powerful.

    2 replies

    rowly23
    rowly23
    Participating Frequently
    August 11, 2026

    I have noticed something similar with AI-generated masks in Photoshop. The generation itself can be reasonably fast, but editing the resulting mask with the Brush tool can become very laggy, especially when trying to make small precise adjustments.

    It might be worth checking whether the issue is related specifically to GPU processing or the complexity of the generated mask. If possible, testing the same mask after rasterizing or simplifying it could help determine whether the mask itself is causing the input lag.

    Since you're on an M1 Ultra and the rest of Photoshop seems to respond normally, it does sound like something specific to how the Harmonize mask is being handled rather than a general performance problem.

    graphics_4075
    graphics_4075Author
    Inspiring
    August 11, 2026

     

    It seems that when adjusting the AI-Generated mask, Photoshop absolutely explodes my CPU usage. This is on a relatively simple, rectangular mask. 

    I just tested the Harmonize function and that sits at around 13% CPU usage while processing. 

     

    2% CPU Usage - “Idle” on mask

     

    165% CPU Usage - After using “Refine Edge” Brush tool

     

    Cheers
    Terms & ConditionsAccessibility statement
    Using the community Terms of use Privacy Cookie preferences Do not sell or share my personal information ad choicesAdChoices