In what ways were these machines failing to run CC/CM? I have used a few different computers, Windows and Mac, tablet, laptop, and tower and so far haven't had any problems.
There may be something else going on, like EM interference when you start/stop the spindle, conflicts with other software you use, etc. that could be causing your issues, independent of the hardware. If you let us know more about the nature of your problem, we might be able to help more.
Just in case it helps, these are the machines I've successfully run CM jobs from (with no errors/problems at all):
* 2012 Apple MacBook Pro 15", i7, 16GB RAM (macOS Sierra)
* Microsoft Surface 4 tablet, i5, 8GB RAM (Windows 10 Pro)
* Dell Precision T3610 workstation, Xeon, 16GB ECC RAM (Windows 10 Pro)
I always keep everything up-to-date with software updates, Mac and PC. With Windows I've used vanilla Windows 10, then later with the Anniversary update, and more recently with the Creators update, it all works.
I've used CM3 with GRBL 0.9, and CM4 with GRBL 1.1 (I've only tried CM4 on Windows, not Mac) there was no difference in compatibility in my experience.