I'm sorry, but you must try to be more accurate with your report. You haven't said:
- the simulator used
- the airplane used
- the airport used
- what you did with GSX
- what do you mean with "at least 20-half hour" ? 20 times half hour, that is 10 hours ? Or you just wanted to say after some time, varying between 20 and 30 minutes ?
- what makes you think the problem is caused by GSX ?