diff --git a/README.md b/README.md
index ae63269..b1a07ee 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ The cross-platform fenster-based single-source bitmap renderer can be compiled w
 
 The performance measurements use OpenMP and can be compiled with:
 
-````g++ -std=c++20 -mavx -fopenmp tiny_bvh_speedtest.cpp -o tiny_bvh_speedtest````
+````g++ -std=c++20 -mavx -Ofast -fopenmp tiny_bvh_speedtest.cpp -o tiny_bvh_speedtest````
 
 # Version
 The current version of the library is a 'prototype'; please expect changes to the interface. Once the interface has settled, more functionality will follow. Plans: