To answer your question, concurrently with MSFS I am running FSUIPC, Aivlasoft EFB v2 (server only, my client is on my second PC), AIG, GAIST (only the relevant regional traffic) and GSX that is all.
On my last flight, I noticed at my departure airport that far less AI aircraft were on MSFS than on my Aivlasoft airport scenery (at least more than 20 less aircraft in the sim than shown on the EFB.