diff --git a/config/templates/mesosphere.mk b/config/templates/mesosphere.mk
index 13dcf296..6205650b 100644
--- a/config/templates/mesosphere.mk
+++ b/config/templates/mesosphere.mk
@@ -9,7 +9,7 @@ include  $(dir $(abspath $(lastword $(MAKEFILE_LIST))))/../common.mk
 ifeq ($(ATMOSPHERE_BUILD_FOR_DEBUGGING),1)
 ATMOSPHERE_OPTIMIZATION_FLAG := -Os
 else
-ATMOSPHERE_OPTIMIZATION_FLAG := -Os
+ATMOSPHERE_OPTIMIZATION_FLAG := -O3
 endif
 
 export DEFINES     := $(ATMOSPHERE_DEFINES) -DATMOSPHERE_IS_MESOSPHERE
diff --git a/libmesosphere/libmesosphere.mk b/libmesosphere/libmesosphere.mk
index d94f97bf..32db7066 100644
--- a/libmesosphere/libmesosphere.mk
+++ b/libmesosphere/libmesosphere.mk
@@ -14,7 +14,7 @@ PRECOMPILED_HEADERS :=  include/mesosphere.hpp
 ifeq ($(ATMOSPHERE_BUILD_FOR_DEBUGGING),1)
 ATMOSPHERE_OPTIMIZATION_FLAG := -Os
 else
-ATMOSPHERE_OPTIMIZATION_FLAG := -Os
+ATMOSPHERE_OPTIMIZATION_FLAG := -O3
 endif
 
 DEFINES	    := $(ATMOSPHERE_DEFINES) -DATMOSPHERE_IS_MESOSPHERE