I am using Lightroom CC 2015.3 with ACR 9.3 and during export the UI becomes so slow it is unusable. It still functions but we are talking in the order of seconds between my input and the application responding. I have a large selection of RAW photos I need to lightly process before exporting to TIFF so they can be imported into an image sequence for use in SpeedGrade. As Lightroom doesn't seem to take advantage of my multi core CPU, this can take an exceptionally long time, to the point where I have to leave it running over night. During the day if I want to export it means I can't use Lightroom for anything else. The specifications of my computer are below, it is an exceptionally powerful workstation for high end video and photography work.
Does anyone have any suggestions on how to improve either the export performance of Lightroom or its responsiveness while it is exporting?
Problem solved. I have abandoned Lightroom and am I now using Capture One Pro from Phase One. It is well designed to take advantage of a multi core CPU and affects the same output I required from Lightroom in 1/10th of the total time required by Lightroom. My CPU usage has gone from 14-18% to 100%.