diff --git dataobj/environment.cc dataobj/environment.cc
index 520fd6441..72afe9eb7 100644
--- dataobj/environment.cc
+++ dataobj/environment.cc
@@ -122,6 +122,7 @@ plainstring env_t::river_type[10];
 uint8 env_t::river_types;
 sint32 env_t::autosave;
 uint32 env_t::fps;
+uint32 env_t::ff_fps;
 sint16 env_t::max_acceleration;
 uint8 env_t::num_threads;
 bool env_t::show_tooltips;
@@ -226,11 +227,10 @@ void env_t::init()
 	// autosave every x months (0=off)
 	autosave = 0;
 
-	// default: make 25 frames per second (if possible)
-	fps=25;
+	fps = 25;
+	ff_fps = 25;
 
-	// maximum speedup set to 1000 (effectively no limit)
-	max_acceleration=50;
+	max_acceleration = 50;
 
 #ifdef MULTI_THREAD
 	num_threads = 4;
@@ -350,6 +350,9 @@ void env_t::rdwr(loadsave_t *file)
 
 	file->rdwr_long( autosave );
 	file->rdwr_long( fps );
+	if (file->is_version_atleast(121, 1)) {
+		file->rdwr_long(ff_fps);
+	}
 	file->rdwr_short( max_acceleration );
 
 	file->rdwr_bool( road_user_info );
diff --git dataobj/environment.h dataobj/environment.h
index dc8e21fd4..4d1443438 100644
--- dataobj/environment.h
+++ dataobj/environment.h
@@ -362,8 +362,10 @@ public:
 	 */
 	/// @{
 
-	/// set the frame rate for the display
-	static uint32 fps;
+	static uint32 fps;                ///< target frame rate
+	static uint32 ff_fps;             ///< target fps during fast forward
+	static const uint32 min_fps = 10; ///< minimum target fps (actual fps may be lower for large zoom out on slow machines)
+	static const uint32 max_fps = 100;
 
 	/// maximum acceleration with fast forward
 	static sint16 max_acceleration;
diff --git dataobj/settings.cc dataobj/settings.cc
index cc62e4dde..e57bbfc8c 100644
--- dataobj/settings.cc
+++ dataobj/settings.cc
@@ -701,7 +701,7 @@ void settings_t::rdwr(loadsave_t *file)
 			random_counter = get_random_seed( );
 			file->rdwr_long( random_counter );
 			if(  !env_t::networkmode  ||  env_t::server  ) {
-				frames_per_second = clamp(env_t::fps,5,100 );	// update it on the server to the current setting
+				frames_per_second = env_t::fps; // update it on the server to the current setting
 				frames_per_step = env_t::network_frames_per_step;
 			}
 			file->rdwr_long( frames_per_second );
@@ -901,7 +901,8 @@ void settings_t::parse_simuconf(tabfile_t& simuconf, sint16& disp_width, sint16&
 	env_t::show_names = contents.get_int("show_names", env_t::show_names );
 	env_t::show_month = contents.get_int("show_month", env_t::show_month );
 	env_t::max_acceleration = contents.get_int("fast_forward", env_t::max_acceleration );
-	env_t::fps = contents.get_int("frames_per_second",env_t::fps );
+	env_t::fps = clamp(contents.get_int("frames_per_second", env_t::fps), env_t::min_fps, env_t::max_fps);
+	env_t::ff_fps = clamp(contents.get_int("ff_frames_per_second", env_t::ff_fps), env_t::min_fps, env_t::max_fps);
 	env_t::num_threads = clamp( contents.get_int("threads", env_t::num_threads ), 1, MAX_THREADS );
 	env_t::simple_drawing_default = contents.get_int("simple_drawing_tile_size",env_t::simple_drawing_default );
 	env_t::simple_drawing_fast_forward = contents.get_int("simple_drawing_fast_forward",env_t::simple_drawing_fast_forward );
diff --git gui/display_settings.cc gui/display_settings.cc
index ce2ea1492..a78b9acb8 100644
--- gui/display_settings.cc
+++ gui/display_settings.cc
@@ -135,7 +135,7 @@ void gui_settings_t::draw(scr_coord offset)
 	idle_time_value_label.update();
 
 	// fps_label
-	uint32 target_fps = world()->is_fast_forward() ? 10 : env_t::fps;
+	uint32 target_fps = world()->is_fast_forward() ? env_t::ff_fps : env_t::fps;
 	uint32 loops = world()->get_realFPS();
 	PIXVAL color = SYSCOL_TEXT_HIGHLIGHT;
 	if(  loops < (target_fps*16*3)/4  ) {
diff --git gui/settings_stats.cc gui/settings_stats.cc
index 2ceabcf1f..f34779fc7 100644
--- gui/settings_stats.cc
+++ gui/settings_stats.cc
@@ -153,7 +153,8 @@ void settings_general_stats_t::read(settings_t* const sets)
 void settings_display_stats_t::init(settings_t const* const)
 {
 	INIT_INIT
-	INIT_NUM( "frames_per_second",env_t::fps, 10, 25, gui_numberinput_t::AUTOLINEAR, false );
+	INIT_NUM( "frames_per_second",env_t::fps, env_t::min_fps, env_t::max_fps, gui_numberinput_t::AUTOLINEAR, false );
+	INIT_NUM( "ff_frames_per_second", env_t::ff_fps, env_t::min_fps, env_t::max_fps, gui_numberinput_t::AUTOLINEAR, false);
 	INIT_NUM( "simple_drawing_tile_size",env_t::simple_drawing_default, 2, 256, gui_numberinput_t::POWER2, false );
 	INIT_BOOL( "simple_drawing_fast_forward",env_t::simple_drawing_fast_forward );
 	INIT_NUM( "water_animation_ms", env_t::water_animation, 0, 1000, 25, false );
@@ -185,6 +186,7 @@ void settings_display_stats_t::read(settings_t* const)
 	READ_INIT
 	// all visual stuff
 	READ_NUM_VALUE( env_t::fps );
+	READ_NUM_VALUE( env_t::ff_fps );
 	READ_NUM_VALUE( env_t::simple_drawing_default );
 	READ_BOOL_VALUE( env_t::simple_drawing_fast_forward );
 	READ_NUM_VALUE( env_t::water_animation );
diff --git simintr.cc simintr.cc
index 852c851eb..c80fc1d2c 100644
--- simintr.cc
+++ simintr.cc
@@ -27,7 +27,9 @@ static main_view_t *welt_ansicht = NULL;
 static uint32 last_time;
 static bool enabled = false;
 
-#define FRAME_TIME_MULTI (16)
+#define FRAME_TIME_PRECISION_BITS (4)
+#define FRAME_TIME_MULTI (1 << FRAME_TIME_PRECISION_BITS)
+
 
 // pause between two frames
 static uint32 frame_time = 36*FRAME_TIME_MULTI;
@@ -35,39 +37,45 @@ static uint32 frame_time = 36*FRAME_TIME_MULTI;
 
 bool reduce_frame_time()
 {
-	if(frame_time > 10*FRAME_TIME_MULTI) {
+	if(  frame_time > 150*FRAME_TIME_MULTI  ) { // < ~6.6fps
+		frame_time -= 8;
+		return true;
+	}
+	else if(frame_time > (FRAME_TIME_MULTI*1000)/env_t::max_fps) {
 		frame_time -= 1;
-		if(  frame_time>150*FRAME_TIME_MULTI  ) {
-			frame_time -= 8;
-		}
 		return true;
 	}
 	else {
-		frame_time = 10*FRAME_TIME_MULTI;
+		frame_time = (FRAME_TIME_MULTI*1000)/env_t::max_fps;
 		return false;
 	}
 }
 
+
 bool increase_frame_time()
 {
-	if(frame_time < 255*FRAME_TIME_MULTI) {
+	if(frame_time > (FRAME_TIME_MULTI*1000)/4) { // < 4 fps
+		return false;
+	}
+	else {
 		frame_time ++;
 		return true;
-	} else {
-		return false;
 	}
 }
 
+
 uint32 get_frame_time()
 {
 	return frame_time/FRAME_TIME_MULTI;
 }
 
+
 void set_frame_time(uint32 time)
 {
-	frame_time = clamp( time, 10, 250 )*FRAME_TIME_MULTI;
+	frame_time = clamp( time, 1000/env_t::max_fps, 1000/env_t::min_fps )*FRAME_TIME_MULTI;
 }
 
+
 void intr_refresh_display(bool dirty)
 {
 	wasser_t::prepare_for_refresh();
@@ -88,24 +96,28 @@ void intr_refresh_display(bool dirty)
 void interrupt_check(const char* caller_info)
 {
 	DBG_DEBUG4("interrupt_check", "called from (%s)", caller_info);
-	if(enabled) {
-		static uint32 last_ms = 0;
-		if(  !welt_modell->is_fast_forward()  ||  welt_modell->get_ticks() != last_ms  ) {
-			const uint32 now = dr_time();
-			if((now-last_time)*FRAME_TIME_MULTI < frame_time) {
-				return;
-			}
-			const sint32 diff = (( (sint32)now - (sint32)last_time)*welt_modell->get_time_multiplier())/16;
-			if(  diff>0  ) {
-				enabled = false;
-				last_time = now;
-				welt_modell->sync_step( diff, !welt_modell->is_fast_forward(), true );
-				enabled = true;
-			}
+	(void)caller_info;
+
+	if(  !enabled  ) {
+		return;
+	}
+
+	static uint32 last_ms = 0;
+	if(  !welt_modell->is_fast_forward()  ||  welt_modell->get_ticks() != last_ms  ) {
+		const uint32 now = dr_time();
+		if((now-last_time)*FRAME_TIME_MULTI < frame_time) {
+			return;
+		}
+
+		const sint32 diff = (( (sint32)now - (sint32)last_time)*welt_modell->get_time_multiplier())/16;
+		if(  diff>0  ) {
+			enabled = false;
+			last_time = now;
+			welt_modell->sync_step( diff, !welt_modell->is_fast_forward(), true );
+			enabled = true;
 		}
-		last_ms = welt_modell->get_ticks();
 	}
-	(void)caller_info;
+	last_ms = welt_modell->get_ticks();
 }
 
 
diff --git simintr.h simintr.h
index 2964aa050..22f1c4731 100644
--- simintr.h
+++ simintr.h
@@ -13,10 +13,14 @@ class karte_t;
 class main_view_t;
 
 
+/// Try to increase fps
 bool reduce_frame_time();
+
+/// Try to decrease fps
 bool increase_frame_time();
+
 uint32 get_frame_time();
-void set_frame_time(uint32 time);
+void set_frame_time(uint32 ms);
 
 
 void intr_refresh_display(bool dirty);
diff --git simmain.cc simmain.cc
index efe945c0a..bbfbd4893 100644
--- simmain.cc
+++ simmain.cc
@@ -454,7 +454,7 @@ int simu_main(int argc, char** argv)
 			" -easyserver         set up every for server (query own IP, port forwarding)\n"
 			" -freeplay           play with endless money\n"
 			" -fullscreen         starts simutrans in fullscreen mode\n"
-			" -fps COUNT          framerate (from 5 to 100)\n"
+			" -fps COUNT          framerate (from %d to %d)\n"
 			" -h | -help | --help displays this help\n"
 			" -lang CODE          starts with specified language\n"
 			" -load NAME          loads savegame with name 'NAME' from Simutrans 'save' directory\n"
@@ -494,7 +494,9 @@ int simu_main(int argc, char** argv)
 			" -times              does some simple profiling\n"
 			" -until YEAR.MONTH   quits when MONTH of YEAR starts\n"
 #endif
-			" -use_workdir        use current dir as basedir\n"
+			" -use_workdir        use current dir as basedir\n",
+
+			env_t::min_fps, env_t::max_fps
 		);
 		return 0;
 	}
diff --git simutrans/config/simuconf.tab simutrans/config/simuconf.tab
index c2e19ad02..4ea8c6ccb 100644
--- simutrans/config/simuconf.tab
+++ simutrans/config/simuconf.tab
@@ -634,6 +634,9 @@ autosave = 0
 # (depends very much on computer, game complexity and graphics driver)
 frames_per_second = 25
 
+# Same as frames_per_second, but for fast forward
+ff_frames_per_second = 25
+
 # during zooming out simutrans may get slow due to the very high number
 # of tiles visible. If the tiles become equal or smaller than the tile size
 # below, a simpler clipping algorithm will be used, which will give some
diff --git simutrans/history.txt simutrans/history.txt
index 2db3a5f5a..4bb206296 100644
--- simutrans/history.txt
+++ simutrans/history.txt
@@ -1,3 +1,5 @@
+	ADD: Fast Forward fps now configurable (ff_frames_per_second in simuconf.tab)
+	FIX: Permanent fps drop when opening settings window with fps > 25
 	FIX: Rotation of multi-tile buildings at street corners
 	ADD: different volumes for different sounds, realistic distance scaling (independent from screen size)
 	CHG: Fade sounds with one over square root distance, and remove the dependency from display and tile size
diff --git simversion.h simversion.h
index c312b2f42..1b530dc21 100644
--- simversion.h
+++ simversion.h
@@ -24,7 +24,7 @@
 // Beware: SAVEGAME minor is often ahead of version minor when there were patches.
 // ==> These have no direct connection at all!
 #define SIM_SAVE_MINOR      0
-#define SIM_SERVER_MINOR    0
+#define SIM_SERVER_MINOR    1
 // NOTE: increment before next release to enable save/load of new features
 
 #define MAKEOBJ_VERSION "60.4"
diff --git simworld.cc simworld.cc
index b4fbf606d..13ad33734 100644
--- simworld.cc
+++ simworld.cc
@@ -3690,9 +3690,11 @@ void karte_t::update_frame_sleep_time()
 			}
 		}
 	}
-	else  { // here only with fyst forward ...
+	else  {
+		assert(step_mode == FAST_FORWARD);
+
 		// try to get 10 fps or lower rate (if set)
-		uint32 frame_intervall = max( 100, 1000/env_t::fps );
+		const uint32 frame_intervall = 1000/env_t::ff_fps;
 		if(get_frame_time()>frame_intervall) {
 			reduce_frame_time();
 		}
@@ -6135,7 +6137,7 @@ void karte_t::reset_timer()
 	else if(step_mode==FAST_FORWARD) {
 		next_step_time = last_tick_sync+1;
 		idle_time = 0;
-		set_frame_time( 100 );
+		set_frame_time( 1000 / env_t::ff_fps );
 		time_multiplier = 16;
 		intr_enable();
 	}