Adobe has finally released Lightroom Classic CC 7.2, which promises boosts in performance. You can update to Adobe Lightroom Classic CC 7.2 right now.
In the past, many users have reported that Lightroom becomes slower after a prolonged usage. This issue should have been fixed with this version. Also, resource-intensive activities, such as export, import, preview generation, and HD/panorama merge should be faster if your machine has 12 GM or more RAM.
We, specifically, have implemented changes related to Threading Building Blocks (TBB). This should be effective on machines with 12 GB or more RAM.
You can head over to Adobe to see the full list of improvements, as well as new cameras supported and bug fixes.