It's been a long time so I have just a vague memory of what I had to do to reduce stuttering on FSX on my machine. I won't even attempt to run 2020 on it, as I'll get a new machine that hopefully can run w/o any stuttering or slowdowns to crappy frame rates when landing/taking off. For those in the know, does 2020 require endless tweaks and uber-expensive video cards to run stutter-free with a frame rate above 30 fps? I prefer a much higher frame rate and I'll not get into an argument with those that are fine with much slower frame rates.
