diff --git a/ref_vk/vk_framectl.c b/ref_vk/vk_framectl.c
index beb2148e..590c52c6 100644
--- a/ref_vk/vk_framectl.c
+++ b/ref_vk/vk_framectl.c
@@ -11,6 +11,9 @@
 #include "vk_staging.h"
 #include "vk_commandpool.h"
 
+#include "vk_light.h" // For stats
+#include "shaders/ray_interop.h" // stats: struct LightCluster
+
 #include "profiler.h"
 
 #include "eiface.h" // ARRAYSIZE
@@ -182,8 +185,13 @@ static void updateGamma( void ) {
 	}
 }
 
-// FIXME move this to r print speeds or something like that
+// FIXME move this to r_speeds or something like that
 static void showProfilingData( void ) {
+	{
+		const int dirty = g_lights.stats.dirty_cells;
+		gEngine.Con_NPrintf(4, "Dirty light cells: %d, estimated size = %dKiB\n", dirty, (int)(dirty * sizeof(struct LightCluster) / 1024));
+	}
+
 	gEngine.Con_NPrintf(5, "Perf scopes:");
 	for (int i = 0; i < g_aprof.num_scopes; ++i) {
 		const aprof_scope_t *const scope = g_aprof.scopes + i;
diff --git a/ref_vk/vk_light.c b/ref_vk/vk_light.c
index cb9aa086..9a5a80cb 100644
--- a/ref_vk/vk_light.c
+++ b/ref_vk/vk_light.c
@@ -536,6 +536,7 @@ void RT_LightsNewMapBegin( const struct model_s *map ) {
 			vk_lights_cell_t *const cell = g_lights.cells + i;
 			cell->num_point_lights = cell->num_static.point_lights = 0;
 			cell->num_polygons = cell->num_static.polygons = 0;
+			cell->dirty = true;
 		}
 	}
 }
@@ -545,10 +546,16 @@ void RT_LightsFrameBegin( void ) {
 	g_lights_.num_point_lights = g_lights_.num_static.point_lights;
 	g_lights_.num_polygon_vertices = g_lights_.num_static.polygon_vertices;
 
+	g_lights.stats.dirty_cells = 0;
+
 	for (int i = 0; i < g_lights.map.grid_cells; ++i) {
 		vk_lights_cell_t *const cell = g_lights.cells + i;
 		cell->num_polygons = cell->num_static.polygons;
 		cell->num_point_lights = cell->num_static.point_lights;
+
+		if (cell->dirty)
+			++g_lights.stats.dirty_cells;
+		cell->dirty = false;
 	}
 }
 
@@ -564,6 +571,7 @@ static qboolean addSurfaceLightToCell( int cell_index, int polygon_light_index )
 	}
 
 	cluster->polygons[cluster->num_polygons++] = polygon_light_index;
+	cluster->dirty = true;
 	return true;
 }
 
@@ -578,6 +586,7 @@ static qboolean addLightToCell( int cell_index, int light_index ) {
 	}
 
 	cluster->point_lights[cluster->num_point_lights++] = light_index;
+	cluster->dirty = true;
 	return true;
 }
 
diff --git a/ref_vk/vk_light.h b/ref_vk/vk_light.h
index 0aee4eee..9bc4a424 100644
--- a/ref_vk/vk_light.h
+++ b/ref_vk/vk_light.h
@@ -16,6 +16,8 @@ typedef struct {
 		uint8_t point_lights;
 		uint8_t polygons;
 	} num_static;
+
+	qboolean dirty;
 } vk_lights_cell_t;
 
 typedef struct {
@@ -57,6 +59,10 @@ typedef struct {
 	} map;
 
 	vk_lights_cell_t cells[MAX_LIGHT_CLUSTERS];
+
+	struct {
+		int dirty_cells;
+	} stats;
 } vk_lights_t;
 
 extern vk_lights_t g_lights;