Press Double "D" to have a look, how many Polygons are Paint. 80 * Guard and 10 * Houses are more than 40000 Polygons. Take a look, how many Polys your Graficcard can Paint in one second. When you have 50 FPS, Your card must Paint over 2Mill Polys in one Second.

Use Models with less Polys, and your programm will run faster.

Please thing about, that every trace make your game also slower.