diff --git a/Cargo.toml b/Cargo.toml
index 0527df63..c5d0b5f5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -49,6 +49,6 @@ strip = true
 overflow-checks = false
 codegen-units = 1
 lto = "fat"
-opt-level = 3
+opt-level = 'z'
 strip = true
 # panic = "abort"