I have a really nice computer, one that can run P3Dv5 pretty much perfectly.  My only issue is at some airports, whenever the dynamic lights come on, it's a stutter show and sometimes just crashes my computer all together.  Other airports with dynamic lights are just fine, with hardly any loss of frames or performance.  Like I can go to FLy Tampa KLAS and have zero loss of performance, but if I go to PACSIM KRNO, it's terrible and causes a computer crash.  I usually run using 4XSSAA, but when I fly at night, I back that down to 2XSSAA.  Any suggestions, other than not flying at these trouble airports at night.

Use 8x MSAA. Turn off shadows.

(P.S. You haven't told us what your specs your "really nice computer" has, nor what settings you run in P3D).

PacSim's KRNO is an older add-on. You might want to try https://forum.inibuilds.com/files/file/1475-pacsim-reno/ which is what I use and don't have FPS issues with my older PC. 

I personally do not think that MSAA in any shape or form is good enough for standard size monitors @ 1920x1080 resolution. I run P3Dv4.5 with 4xSSAA at all times, although the only night that I experience is at dawn or dusk. I agree with Deltaguy that performance with dynamic lights enabled can be extremely variable. As an example, I recently added the IniBuilds dynamic lighting updates at MK Studios Dublin and FlyTampa Copenhagen Kastrup. Whilst I am not able to detect any performance issues at Copenhagen (yes, this is with 4xSSAA enabled), the framerate at Dublin when close to the terminal buildings takes quite a hit. I even added the IniBuilds dynamic lighting update at Aerosoft Heathrow Professional because of my experience with Copenhagen, and performance at this massive airport is considerably better when close to the terminals than it is at Dublin.

Edited January 30, 20224 yr by Christopher Low