diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2ac82b6..4b10435 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -118,26 +118,28 @@ elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
 	endif()
 	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${MSVC_EXTRA_FLAGS}")
 
-	# Speed Optimized Configuration
-	set(_SPEED_COMPILER_FLAGS "/O2 /Oi /Ot /Oy /GF /GS- /Qpar /arch:AVX /GR /GL")
-	set(_SPEED_LINKER_FLAGS "/LTCG:incremental /OPT:ICF=4 /INCREMENTAL /OPT:REF")
-	set(CMAKE_CXX_FLAGS_SPEED "${CMAKE_CXX_FLAGS_RELWTIHDEBINFO} ${_SPEED_COMPILER_FLAGS}")
-	set(CMAKE_C_FLAGS_SPEED "${CMAKE_C_FLAGS_RELWTIHDEBINFO} ${_SPEED_COMPILER_FLAGS}")
-	set(CMAKE_EXE_LINKER_FLAGS_SPEED "${CMAKE_EXE_LINKER_FLAGS_RELWTIHDEBINFO} ${_SPEED_LINKER_FLAGS}")
-	set(CMAKE_SHARED_LINKER_FLAGS_SPEED "${CMAKE_EXE_LINKER_FLAGS_RELWTIHDEBINFO} ${_SPEED_LINKER_FLAGS}")
-	set(CMAKE_MODULE_LINKER_FLAGS_SPEED "${CMAKE_EXE_LINKER_FLAGS_RELWTIHDEBINFO} ${_SPEED_LINKER_FLAGS}")
-	mark_as_advanced(
-		CMAKE_CXX_FLAGS_SPEED
-		CMAKE_C_FLAGS_SPEED
-		CMAKE_EXE_LINKER_FLAGS_SPEED
-		CMAKE_SHARED_LINKER_FLAGS_SPEED
-		CMAKE_MODULE_LINKER_FLAGS_SPEED
-	)
+	if("${PropertyPrefix}" STREQUAL "")
+		# Speed Optimized Configuration
+		set(_SPEED_COMPILER_FLAGS "/O2 /Oi /Ot /Oy /GF /GS- /Qpar /arch:AVX /GR /GL")
+		set(_SPEED_LINKER_FLAGS "/LTCG:incremental /OPT:ICF=4 /INCREMENTAL /OPT:REF")
+		set(CMAKE_CXX_FLAGS_SPEED "${CMAKE_CXX_FLAGS_RELWTIHDEBINFO} ${_SPEED_COMPILER_FLAGS}")
+		set(CMAKE_C_FLAGS_SPEED "${CMAKE_C_FLAGS_RELWTIHDEBINFO} ${_SPEED_COMPILER_FLAGS}")
+		set(CMAKE_EXE_LINKER_FLAGS_SPEED "${CMAKE_EXE_LINKER_FLAGS_RELWTIHDEBINFO} ${_SPEED_LINKER_FLAGS}")
+		set(CMAKE_SHARED_LINKER_FLAGS_SPEED "${CMAKE_EXE_LINKER_FLAGS_RELWTIHDEBINFO} ${_SPEED_LINKER_FLAGS}")
+		set(CMAKE_MODULE_LINKER_FLAGS_SPEED "${CMAKE_EXE_LINKER_FLAGS_RELWTIHDEBINFO} ${_SPEED_LINKER_FLAGS}")
+		mark_as_advanced(
+			CMAKE_CXX_FLAGS_SPEED
+			CMAKE_C_FLAGS_SPEED
+			CMAKE_EXE_LINKER_FLAGS_SPEED
+			CMAKE_SHARED_LINKER_FLAGS_SPEED
+			CMAKE_MODULE_LINKER_FLAGS_SPEED
+		)
 
-	if(CMAKE_CONFIGURATION_TYPES)
-		list(APPEND CMAKE_CONFIGURATION_TYPES Speed)
-		list(REMOVE_DUPLICATES CMAKE_CONFIGURATION_TYPES)
-		CacheSet(CMAKE_CONFIGURATION_TYPES "${CMAKE_CONFIGURATION_TYPES}")
+		if(CMAKE_CONFIGURATION_TYPES)
+			list(APPEND CMAKE_CONFIGURATION_TYPES Speed)
+			list(REMOVE_DUPLICATES CMAKE_CONFIGURATION_TYPES)
+			CacheSet(CMAKE_CONFIGURATION_TYPES "${CMAKE_CONFIGURATION_TYPES}")
+		endif()
 	endif()
 endif()