diff --git a/Makefile b/Makefile
index f1146d9..01ca1ff 100644
--- a/Makefile
+++ b/Makefile
@@ -216,7 +216,7 @@ qemu: fs.img xv6.img
 	$(QEMU) -serial mon:stdio $(QEMUOPTS)
 
 qemu-memfs: xv6memfs.img
-	$(QEMU) xv6memfs.img -smp $(CPUS)
+	$(QEMU) xv6memfs.img -smp $(CPUS) -m 256
 
 qemu-nox: fs.img xv6.img
 	$(QEMU) -nographic $(QEMUOPTS)