I've noticed that if I use the highlights slider to reduce highlights, it just completely destroys Lightroom performance. I have been applying a preset to all my images on import that (in addition to other things*) sets Highlights to -30, and I discovered that doing so caused my machine to take over 5 seconds to swap between images (fully slamming all 8 cores of this 2.7GHhz i7-6820HK Lenovo P50 Laptop (16GB Ram, super-fast NVMe SSD). Even after the UI becomes accessible, it isn't done processing. If I touch the brightness slider or any other, it is very slow to respond. However, if I leave the highlights slider at zero on everything, it takes less than a second to cycle between different images.
Other notes about my setup and things I have tried:
1. I have tried keeping a separate partition for the preview cache (had no effect)
2. I have tried all the different types of previews (including changing the resolution of the previews) (had no effect)
3. I am running on a 1920x1200 monitor (though it's just as slow on 1920x1080), latest video drivers.
4. It runs faster on my desktop workstation (3.3GHz i7-5820K with 32GB RAM, everything on SSD), but still slow (3-4 seconds just to go between images)
5. Sometimes performance will just suddenly get stuck being drastically worse (~10 seconds to cycle between images), to the point where I need to reboot Lightroom to get it back up to 'speed'. This poor performance and random drastic worsening has happened across four different machines I've used Lightroom on (aforementioned workstation and P50 laptop, a 2012 Macbook Pro, and a Dell XPS 15 (i7-6700 and NVMe SSD)).
6. The files are 42 megapixel Sony A7RII ARW files and 24 megapixel Sony A6300 ARW files.
7. I am using Lightroom 6.7 and have tried the new 'use smart previews instead of Originals for image editing option', but it did not improve this aspect of performance.
8. This is on Windows 7 (though the Dell XPS 15 was running Windows 10 and it felt even slower)
To work around it, I have changed my workflow so it doesn't auto-apply highlights adjustment, then once I've done all my edits, I select everything and apply a preset that just does the highlights adjustment, but that's pretty poor (since I'm not seeing the output with highlights reduces as I'm making my adjustments.
The question is: is there any way to improve of Lightroom when adjusting Highlights? The other top tier raw editors (Capture One, DxO just blaze through even when HDR edits have been made, so it feels like it should be possible).
* The other things are: bumping exposure, adjusting whites, blacks the tone curve, sharpening, noise reduction and enabling lens profile corrections
I'm not seeing this on my end.
With your fast CPU and the resolution of your monitor (1920x1200) I suggest to make sure that the GPU acceleration is turned off.
I'm not noticing this, but it seams to be a common complaint that LR is slow. I do not have Capture One or DxO, so I cannot judge on the difference, but there are some parameters you can tweak.
Both can be set in the preferences: