diff --git a/scram-tools.file/tools/gcc/gcc-ccompiler.xml b/scram-tools.file/tools/gcc/gcc-ccompiler.xml
index 7f52af37a55..31f82239cf1 100644
--- a/scram-tools.file/tools/gcc/gcc-ccompiler.xml
+++ b/scram-tools.file/tools/gcc/gcc-ccompiler.xml
@@ -4,5 +4,5 @@
       <environment name="CC" value="$GCC_CCOMPILER_BASE/bin/gcc@COMPILER_NAME_SUFFIX@"/>
     </client>
     <flags CSHAREDOBJECTFLAGS="-fPIC @GCC_CSHAREDOBJECTFLAGS@"/>
-    <flags CFLAGS="-O2 -pthread @GCC_CFLAGS@"/>
+    <flags CFLAGS="-O3 -pthread @GCC_CFLAGS@"/>
   </tool>
diff --git a/scram-tools.file/tools/gcc/gcc-cxxcompiler.xml b/scram-tools.file/tools/gcc/gcc-cxxcompiler.xml
index 79c01edf074..3063db6dd48 100644
--- a/scram-tools.file/tools/gcc/gcc-cxxcompiler.xml
+++ b/scram-tools.file/tools/gcc/gcc-cxxcompiler.xml
@@ -5,7 +5,7 @@
     </client>
     <flags CPPDEFINES="GNU_GCC _GNU_SOURCE @GCC_CPPDEFINES@"/>
     <flags CXXSHAREDOBJECTFLAGS="-fPIC @GCC_CXXSHAREDOBJECTFLAGS@"/>
-    <flags CXXFLAGS="-O2 -pthread -pipe -Werror=main -Werror=pointer-arith"/>
+    <flags CXXFLAGS="-O3 -pthread -pipe -Werror=main -Werror=pointer-arith"/>
     <flags CXXFLAGS="-Werror=overlength-strings -Wno-vla @GCC_CXXFLAGS@"/>
     <flags CXXFLAGS="-felide-constructors -fmessage-length=0"/>
     <flags CXXFLAGS="-Wall -Wno-non-template-friend -Wno-long-long -Wreturn-type"/>
diff --git a/scram-tools.file/tools/gcc/gcc-f77compiler.xml b/scram-tools.file/tools/gcc/gcc-f77compiler.xml
index 5852618e76a..f63f1e1ca1d 100644
--- a/scram-tools.file/tools/gcc/gcc-f77compiler.xml
+++ b/scram-tools.file/tools/gcc/gcc-f77compiler.xml
@@ -5,8 +5,8 @@
       <environment name="GCC_F77COMPILER_BASE" default="@TOOL_ROOT@"/>
       <environment name="FC" default="$GCC_F77COMPILER_BASE/bin/gfortran"/>
     </client>
-    <flags FFLAGS="-fno-second-underscore -Wunused -Wuninitialized -O2 @GCC_FFLAGS@"/>
+    <flags FFLAGS="-fno-second-underscore -Wunused -Wuninitialized -O3 @GCC_FFLAGS@"/>
     <flags FFLAGS="-std=legacy"/>
-    <flags FOPTIMISEDFLAGS="-O2 @GCC_FOPTIMISEDFLAGS@"/>
+    <flags FOPTIMISEDFLAGS="-O3 @GCC_FOPTIMISEDFLAGS@"/>
     <flags FSHAREDOBJECTFLAGS="-fPIC @GCC_FSHAREDOBJECTFLAGS@"/>
   </tool>