Turn the Hyperthreading off, run DCS and check the CPU utilization. If at 100%, turn the Hyper on. You have to fill the physical cores before to fill the others. Hyperthreading improve the performance by 20% when all cores are used.
Don't know if i'm right,i think running an aircraft in DCS needs 2-3 cores.
Then, you have to addition more cores to run the objects depending on your appetite.