These were built on Ubuntu 18.04 / WSL on a Windows 10 Pro x64 i7-8750H system. See the mfactor bits table attached to post one of this thread. See also for an indication of what is possible on Knight's Landing and many threads on Linux,
https://www.mersenneforum.org/showpo...&postcount=165
Top of reference tree:
https://www.mersenneforum.org/showpo...22&postcount=1