Krita, Windows - Blur filter is heavily slowing down Krita

Krita 5.3 on Windows 11.

Issue:

Some time ago I made a test with an old render image of mine (1200 x 900 16bit integer) for testing a non-destructive glow effect. I consider this a simple, non demanding task.

The setup uses blur filters.

Those blur filters are slowing down Krita heavily.

I am posting because I like to ask if I should post this as a bug, to let the devs know about the issue?

File to test

Example

Enabling the groups which contain the blur filter:

(right click → watch in new tab or window to see the gif better / bigger - ignore the bad image quality, I had to compress heavily to get below the 3 MB upload limit)

Krita_Speed

If I disable the blur, everything goes faster.

I crosschecked with other image editing software. In those, the blur is fast - no delay or waiting for image operation to complete.

Test setup: Krita 5.3 on a notebook (a decent machine) - Windows 11.

CPU: Intel Core i7 - 10750H (6 cores, 12 threads)

  • Max Turbo Frequency: 5.00 GHz
  • Processor Base Frequency: 2.60 GHz

Ram: 16 GB
Storage: NVMe SSD
GPU: Nvidia RTX 2070 MaxQ + Intel® UHD Graphics

As you can see, the CPU’s potential is not really used.

The setup - relevant is the blur filter: