Catalina has a strict 15-port limit. A "Top" case usually has many USB ports on the front and back.

This is where novices fail. For a Top build:


You must enter your motherboard BIOS and apply the following settings:

Unlike newer macOS versions that force AVX2.0 instructions (breaking older Xeons), Catalina runs perfectly on Intel 4th Gen (Haswell) up to 10th Gen (Comet Lake) . 11th, 12th, and 13th Gen Intel require iGPU spoofing, which adds latency. For a "Top" build, we stick to native support.


To match a top-tier 9th Gen CPU, you need a Z390 chipset motherboard.