diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index 219ea415b..32fa27aa8 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -851,6 +851,7 @@ namespace DoExport {
 	                if (region.config().get_abs_value("perimeter_speed") == 0 ||
 	                    region.config().get_abs_value("small_perimeter_speed") == 0 ||
 	                    region.config().get_abs_value("external_perimeter_speed") == 0 ||
+	                    region.config().get_abs_value("overhang_speed") == 0 ||
 	                    region.config().get_abs_value("bridge_speed") == 0)
 	                    mm3_per_mm.push_back(layerm->perimeters().min_mm3_per_mm());
 	                if (region.config().get_abs_value("infill_speed") == 0 ||
diff --git a/src/libslic3r/Layer.cpp b/src/libslic3r/Layer.cpp
index 35b4a331a..2ace05a9a 100644
--- a/src/libslic3r/Layer.cpp
+++ b/src/libslic3r/Layer.cpp
@@ -474,6 +474,7 @@ void Layer::make_perimeters()
     		                && config.perimeters                  == other_config.perimeters
     		                && config.perimeter_speed             == other_config.perimeter_speed
     		                && config.external_perimeter_speed    == other_config.external_perimeter_speed
+    		                && config.overhang_speed              == other_config.overhang_speed
     		                && (config.gap_fill_enabled ? config.gap_fill_speed.value : 0.) == 
                                (other_config.gap_fill_enabled ? other_config.gap_fill_speed.value : 0.)
     		                && config.overhangs                   == other_config.overhangs