The performance of NinjaTrader 8 and MZpack indicators depends mainly on the complexity of your charts and intensity of the order flow of your instrument, but not the CPU performance. Note, 1 instrument and 10 instances of indicators will create significantly bigger load on your CPU than 2 instruments and 5 instances of indicators per each instrument.
The minimal system requirements are Intel Core i3/4Gb for 3-5 instances of indicators.
We recommend AMD Ryzen/Intel Core i7 (3.0+ GHz) with 16+ Gb of RAM for up to 8-10 instances of indicators. Note, that other 3rd party or built-in indicators that you might use will create additional load on your machine.
The recommended minimum number of cores is 4. Note, in NinjaTrader 8 single-core performance is more important than the number of cores. So, 4 cores/3.8GHz CPU will have better performance than 8 cores/2.8GHz CPU.