diff --git a/src/bin/wasm2obj.rs b/src/bin/wasm2obj.rs
index 6b8bd8287eb6..50cc195299f7 100644
--- a/src/bin/wasm2obj.rs
+++ b/src/bin/wasm2obj.rs
@@ -225,7 +225,7 @@ fn handle_module(
     }
 
     if enable_optimize {
-        flag_builder.set("opt_level", "best").unwrap();
+        flag_builder.set("opt_level", "speed").unwrap();
     }
 
     let isa = isa_builder.finish(settings::Flags::new(flag_builder));
diff --git a/src/bin/wast.rs b/src/bin/wast.rs
index a05acb0631f1..78c31db0df9a 100644
--- a/src/bin/wast.rs
+++ b/src/bin/wast.rs
@@ -144,7 +144,7 @@ fn main() {
 
     // Enable optimization if requested.
     if args.flag_optimize {
-        flag_builder.set("opt_level", "best").unwrap();
+        flag_builder.set("opt_level", "speed").unwrap();
     }
 
     // Enable SIMD if requested