diff --git a/config.mk b/config.mk
index e9a2a602..7ce645ef 100644
--- a/config.mk
+++ b/config.mk
@@ -18,7 +18,7 @@ INCS = -I. -I/usr/include -I${X11INC} `pkg-config --cflags libconfuse xft cairo`
 LIBS = -L/usr/lib -lc -L${X11LIB} -lX11 `pkg-config --libs libconfuse xft cairo` -lXext -lXrandr -lXinerama
 
 # flags
-CFLAGS = -fgnu89-inline -std=gnu99 -ggdb3 -pipe -Wall -Wextra -W -Wchar-subscripts -Wundef -Wshadow -Wcast-align -Wwrite-strings -Wsign-compare -Wunused -Wuninitialized -Winit-self -Wpointer-arith -Wredundant-decls -Wno-format-zero-length -Wmissing-prototypes -Wmissing-format-attribute -Wmissing-noreturn -O0 ${INCS} -DVERSION=\"${VERSION}\"
+CFLAGS = -fgnu89-inline -std=gnu99 -ggdb3 -pipe -Wall -Wextra -W -Wchar-subscripts -Wundef -Wshadow -Wcast-align -Wwrite-strings -Wsign-compare -Wunused -Wuninitialized -Winit-self -Wpointer-arith -Wredundant-decls -Wno-format-zero-length -Wmissing-prototypes -Wmissing-format-attribute -Wmissing-noreturn -O3 ${INCS} -DVERSION=\"${VERSION}\"
 LDFLAGS = -ggdb3 ${LIBS}
 
 # compiler and linker