As was said either by using LOCFG or manually editing the graphics.cfg file you can run Lock-On in any resolution without stretching.
I'm running on a Dell 27" @ 1920x1200 so have the following entry.
}
DisplayMode
{
resolution = {1920, 1200};
bpp = 32;
fullscreen = 1;
aspect = 1.6;
Interface
{
resolution = {1920, 1200};
bpp = 32;
fullscreen = 1;
aspect = 1.6;
}
Simulation
{
resolution = {1920, 1200};
bpp = 32;
fullscreen = 1;
aspect = 1.6;
}
AVI
{
resolution = {640, 480};
fullscreen = 0;
aspect = 1.3333;
}
}
Not too sure on your personal FPS hit but should be a minimum hit with your system. Depends upon your ingame settings.
ATM with everything max (except water @ high) I'm looking @ 40-50 fps average in the su-25T pit so you should have roughly similar results.