I have traced most of Mach problems to just not having enough computing power.
I run Mach3 on a 1Ghz Pentium III with I think 1Ghz of RAM, and it works fine. Mach3 was written to run on Windows 2000, It doesn't need a lot of power.

EMC was always open source, and I believe that when Art wrote Mach3, he based it on some of the original EMC code, so he didn't have to re-invent the wheel.