I’ll just add that you need to change some options in the simulation window to take full advantage:
Before simulating your project click on the Schedulers button, then choose the CIDF MTScheduler. If it is not there then just add it by clicking Add.
Then click the Setup button and match the number of calculation threads to the number of cores on your computer (or the number of threads you would like to run).
The benefit of multithreading will depend on how parallel your system is. I was easily getting simulation speeds 3 times faster on an OFDM sample file.
Try it out!