diff --git a/CMakeLists.txt b/CMakeLists.txt
index fe812f2e4..7d4cabd89 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -225,6 +225,7 @@ if( MSVC )
 	string(REPLACE "/MD " " " CMAKE_CXX_FLAGS_RELEASE ${CMAKE_CXX_FLAGS_RELEASE} )
 	string(REPLACE "/MD " " " CMAKE_CXX_FLAGS_MINSIZEREL ${CMAKE_CXX_FLAGS_MINSIZEREL} )
 	string(REPLACE "/MD " " " CMAKE_CXX_FLAGS_RELWITHDEBINFO ${CMAKE_CXX_FLAGS_RELWITHDEBINFO} )
+	string(REPLACE "/Ob1 " "/Ob2 " CMAKE_CXX_FLAGS_RELWITHDEBINFO ${CMAKE_CXX_FLAGS_RELWITHDEBINFO} )
 	string(REPLACE "/MDd " " " CMAKE_CXX_FLAGS_DEBUG ${CMAKE_CXX_FLAGS_DEBUG} )
 	string(REPLACE "/MD " " " CMAKE_C_FLAGS_RELEASE ${CMAKE_C_FLAGS_RELEASE} )
 	string(REPLACE "/MD " " " CMAKE_C_FLAGS_MINSIZEREL ${CMAKE_C_FLAGS_MINSIZEREL} )