@SnowMiku I don't use DPP4, but I had time to check how what you described runs.
Did you check to see if you can enable the option here?
Under Tools>Preferences>Image Processing 2>Graphic processor settings, do you have the box checked? (it's a dual purpose checkmark for viewing/editing).
Now for my results... (note: I'm running latest and greatest from AMD & Nvidia, w/ 32GB of ram).
When loading a folder to view images (max size/quality jpg & cr3 mixed), I noticed a slight improvement w/ GPU acceleration on vs when off. Barely any difference for first initial load of the image (cr3), as both were almost instant. However, for your example... it just seems slow to get that spinning circle to finish after initial load (cr3).
When I first loaded the program it took 19 seconds regardless of GPU being enabled or not to load the cr3's. However, I also noticed I had the "Cannot apply Digital Lens Optimizer. Use the tool palette to download the lens data." mouse-over message showing. So after figuring out how to download the lens profiles, I reran the tests.
The spinning circle then took 1min 9 seconds to stop w/o GPU. Ran again w/ GPU and it took about 51 seconds. To remove the spindle drive as being a bottleneck (large 7200rpm), I used images on my M2 and reran w/ GPU and that took 44 seconds to finish spinning... so there is a disk factor in the spinning circle.
Since I didn't originally have the lens data loaded, I can only assume the extra overhead is coming from applying that.
I checked a few jpgs to see what that would do in regards to the spinning circle, and it was virtually instant (<=1 sec) with GPU and maybe 1-2 seconds to stop spinning w/o GPU.
@GreenViper It sounds like you were using DxO PhotoLab since you mentioned DeepPRIME. I believe the OP is specifically talking about Cannon's Digital Photo Professional 4. I almost made the same mistake... and was just about to open that program too.
