I posted this elsewhere but I think it is of relevance here as well.
I did a quantitative test. Such a test seems to be lacking on discussion pages re LR memory needs and performance. My computer: iMac retina 5K, 27 inch, 2019, Mohave 10.14.6. LR is most up to date version of Lightroom Classic 8.3.1, Radeon Pro 580X 8Gb memory on the board. I'll get into computer memory in a moment. Working with RAW files from Nikon Z7 with typical size of 60 Mb.
1. iMac arrived with 8 Gb memory installed. Did and HDR merge in LR with three images Took about a minute. Way too long for simple operation so I did not do subsequent tests with this amount of memory.
2. Put in2 x 16 GB OWC memory chips via Amazon. Did a test require HDR AND Pano merge - 18 images total (about 60-65-Mb each) with 3 images HDR set at each of 6 positions for the Pano. Took 1m 38s for LR to create the Pano in preview mode. Took an addition 1m 44s to creat the final image - a Pano with each segment an HDR image for total of 3m 22s. Clearly much better than simple 8 Gb.
3. so I upped the ante going to 4 x 16 chips for total of 64GB. Repeated same test as in example 2. This time it took 1m 10s to generate preview in Pano mood. A modes improvement of almost 30s. But then I let it go ahead to create final image. This took an addition 36s for a total of 1 46s ABOUT TWICE AS FAST AS WITH 32Mb. Amazing.