Have been trying multiple new things - High Sierra GM build, RX580 egpu, new Native Instruments Mikro, updated software (Adobe), etc. nMP upgraded to 8 core 3.3, 32GB. Thunderbolt Display. Now getting random lockups and/or beach balls where I only have a mouse cursor. Have done a PRAM reset, am unplugging all USB devices and so on. Any thoughts or suggestions on debugging the situation, any utilities that may help? Will upgrade to production High Sierra tomorrow to see if that helps.