Just uninstalled old Calibre version, installed new version, and I was happy to see that all my plug-ins and the DRM tools were still active and working. Checking the RAM usage while converting some books still only used 3.99 GB, but the conversion seemed to be 4-5 times faster than before. CPU usage % seemed to drop slightly. I have 4 cores, and the program was using all 4 cores.
Thank you, Mr. Goyal, and all your developer partners, for being sensitive to Calibre users needs and suggestions. I cannot stress enough for all Calibre users that like this software donate towards your project. I tried to write a short program in basic some 30 years ago to process amortorations (Spelling) for mortgages, and I ended up with 1/2 of a legal pad filled with code. I was successful eventually (could have done the calculations more quickly by hand,) but I decided quickly that I was a software user and not a programmer.
Been using computers for over 30 years, and I've never used a program more feature rich and comprehensively useful than Calibre. Kudos to you, Sir!