This particular desktop is an I-7 clocking at 3.4 Ghz with 16MB RAM and a GTX 1080 graphics card. I run an SSD for the OS, but not the Catalog, there's not enough room on the SSD.
I think I'll replace it, or one of the other drives with a bigger SSD and see if that helps.
EDIT: What I really should do is upgrade the motherboard and use an SSD with a PCIe Gen 3.0 x4, NVMe 1.3 interface.
Try moving your catalog and previews to the SSD, but not the raws themselves. You don't need to import the raws to an SSD to benefit from the speed in LR or C1...just the previews as that's what the software works off while you're processing. Once the raws are imported and previews are generated, LR/C1 doesn't read the raws again until you export.
The benefit of storing raws to an SSD is that the importing and exporting process will be faster. I store raws that I am currently working on to an external SSD since I am batch exporting stuff for gigs and it speeds up my workflow, but once they are done the raws get stored on my 8TB HDD within the same catalog.