diff --git a/CMakeLists.txt b/CMakeLists.txt
index ebd02b20..07a292e0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -91,7 +91,7 @@ endif()
 
 if (CMAKE_GENERATOR MATCHES "^Visual Studio.*$")
   message(STATUS "Note: when building with Visual Studio the build type is specified when building.")
-  message(STATUS "For example: 'cmake --build . --config=Release")  
+  message(STATUS "For example: 'cmake --build . --config=Release")
 endif()
 
 if("${CMAKE_BINARY_DIR}" MATCHES ".*(S|s)ecure$")
@@ -401,9 +401,9 @@ if(CMAKE_C_COMPILER_ID MATCHES "AppleClang|Clang|GNU|Intel")
   endif()
   if(MI_OPT_ARCH)
     if(MI_ARCH STREQUAL "x64")
-      set(MI_OPT_ARCH_FLAGS "-march=haswell;-mavx2")    # fast bit scan (since 2013)
+      set(MI_OPT_ARCH_FLAGS "-march=haswell;-mavx2;-mtune=native")    # fast bit scan (since 2013)
     elseif(MI_ARCH STREQUAL "arm64")
-      set(MI_OPT_ARCH_FLAGS "-march=armv8.1-a")         # fast atomics (since 2016)
+      set(MI_OPT_ARCH_FLAGS "-march=armv8.1-a;-mtune=native")         # fast atomics (since 2016)
     endif()
   endif()
 endif()
@@ -557,7 +557,7 @@ if(MI_BUILD_SHARED)
     elseif(MI_ARCH STREQUAL "x64")
       set(MIMALLOC_REDIRECT_SUFFIX "")
       if(CMAKE_SYSTEM_PROCESSOR STREQUAL "ARM64")
-        message(STATUS "Note: x64 code emulated on Windows for arm64 should use an arm64ec build of 'mimalloc-override.dll'") 
+        message(STATUS "Note: x64 code emulated on Windows for arm64 should use an arm64ec build of 'mimalloc-override.dll'")
         message(STATUS "      with 'mimalloc-redirect-arm64ec.dll'. See the 'bin\\readme.md' for more information.")
       endif()
     elseif(MI_ARCH STREQUAL "x86")
@@ -681,7 +681,7 @@ endif()
 # -----------------------------------------------------------------------------
 if (MI_OVERRIDE)
   if (MI_BUILD_SHARED)
-    target_compile_definitions(mimalloc PRIVATE MI_MALLOC_OVERRIDE)    
+    target_compile_definitions(mimalloc PRIVATE MI_MALLOC_OVERRIDE)
   endif()
   if(NOT WIN32)
     # It is only possible to override malloc on Windows when building as a DLL.