during the last days I created about 50 HDR/dng files (Canon 5D3, 3 images merged) using the new LR CC HDR Merge function.
Now, after the merge, when I edit the dng file (22 MPixel, 85 MB) LR slows down extremely.
The main performance issue is not changing the sliders but waiting until the image is rerendered!
After a development change it takes often 10-20 (!) seconds until the image is rendered.
In library module, mostly I have to wait 20 to 40 seconds until a preview is rendered.
Often I wait forever and the preview is NOT rendered. Then I have to restart LR and then again have to wait 20-40 seconds until the image is rendered.
During rendering about 50% of a i7-3770 CPU (i.e. 2 cores are fully loaded!) are used. Sometimes the CPU load goes up to 100% (i.e. 4 cores are used!) during rendering the image.
Below is an example of the load while rendering a preview for more than 2 minutes.
The worst case is using the compare mode in library module. When comparing 2 HDR/dng files, I have to wait sometime 60+ seconds until both previews are rendered.
This is an unacceptable waste of my working time!
I would like to edit images and I do NOT like to wait 20 to 40 seconds VERY OFTEN until the image is rendered and until I can continue to edit the image.
Please investigate this strange behaviour!
BTW: I use a NEC 30 inch display with 2560x1600px. Performance issues are independant if I enable/disable GPU support.