3 minutes to load is unheard of. It shouldn't take more than 10-15 seconds, on a properly configured system.
However, on FSX (depending on which video card you have and how much VRAM it has) it's possible your system is so overloaded with addons and too high settings, that both your video memory and system memory are close to exhaustion, causing a sharp drop in performances.
Some of the options that can help are:
- Lowering the Max texture size slider. On FSX:SE, the last notch is 4K, the second to last is 2K and the third to last is 1024x1024. Try 1024x1024 and see if things gets better.
- Lower the Autogen Density
- Lower the Level of Detail Radius
KCLT has additional options that might reduce the memory footprint in its own YouControl menu (CTRL+F12)
- Disable 3D Cars on Parkings
- Disable Ground Traffic