I just installed Cura 5.2.1 and sliced a model that I had previously sliced in Cura 5.1. It estimated a print time of 10HR 50min with 5.1 and 6HR 54MIn with 5.2.1, both with the same setting. That is a big difference. It will be interesting to see if it actually prints in that time or is something out of wack. Could be a moth in the slicer!
OK I screwed up. I forgot that I scaled the first one up 50% so it would take much longer. DOH!