trying
Code:
#include <acknex.h>


void main()
{
	wait(1);
	
	int i;
	var draw_line_time1, draw_line_time2, draw_quad_time1, draw_quad_time2;
	while (1)
	{
		
		timer();
		
		//test1
		draw_line(NULLVECTOR, NULL, 100);
		
		for (i = 0; i < screen_size.y; i++)
		{
			draw_line(vector(0, i, 0), COLOR_WHITE, 100);
			draw_line(vector(screen_size.x, i, 0), COLOR_WHITE, 100);
		}
		
		draw_line_time1 = timer();
		
		//test2
		draw_quad(NULL, NULLVECTOR, NULL, screen_size, NULL, COLOR_WHITE, 100, 0);
		
		draw_quad_time1 = timer();
		
		//test3
		draw_quad(NULL, NULLVECTOR, NULL, screen_size, NULL, COLOR_WHITE, 100, 0);
		
		draw_quad_time2 = timer();
		
		//test4
		draw_line(NULLVECTOR, NULL, 100);
		
		for (i = 0; i < screen_size.y; i++)
		{
			draw_line(vector(0, i, 0), COLOR_WHITE, 100);
			draw_line(vector(screen_size.x, i, 0), COLOR_WHITE, 100);
		}
		
		draw_line_time2 = timer();
		
		DEBUG_VAR(draw_line_time1, 10);
		DEBUG_VAR(draw_quad_time1, 30);
		DEBUG_VAR(draw_line_time2, 50);
		DEBUG_VAR(draw_quad_time2, 70);
		
		wait (1);
	}
}

will give you an unexplainable result. changing the order you draw shows draw_line as being quicker