diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4ade6346..81490582 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,11 +29,15 @@ SET(ASM_SCALERS_DEFAULT OFF)
 SET(MMX_DEFAULT OFF)
 
 # turn asm on by default on 32bit x86
-IF(CMAKE_SYSTEM_PROCESSOR MATCHES "[xX]86|[aA][mM][dD]64|[xX]64"
-   AND CMAKE_C_SIZEOF_DATA_PTR EQUAL 4)
-    SET(ASM_CORE_DEFAULT ON)
-    SET(ASM_SCALERS_DEFAULT ON)
-    SET(MMX_DEFAULT ON)
+IF(CMAKE_SYSTEM_PROCESSOR MATCHES "[xX]86|[aA][mM][dD]64|[xX]64")
+    IF(CMAKE_C_SIZEOF_DATA_PTR EQUAL 4) # 32 bit
+        SET(ASM_CORE_DEFAULT ON)
+        SET(ASM_SCALERS_DEFAULT ON)
+        SET(MMX_DEFAULT ON)
+        SET(X86_32 ON)
+    ELSE()
+        SET(AMD64 ON)
+    ENDIF()
 ENDIF()
 
 option( ENABLE_ASM_CORE "Enable x86 ASM CPU cores" ${ASM_CORE_DEFAULT})
@@ -54,6 +58,14 @@ ENDIF()
 
 option(ENABLE_FFMPEG "Enable ffmpeg A/V recording" ${FFMPEG_DEFAULT})
 
+SET(LTO_DEFAULT ON)
+
+IF(AMD64 AND WIN32 AND CMAKE_COMPILER_IS_GNUCXX)
+    SET(LTO_DEFAULT OFF)
+ENDIF()
+
+OPTION(ENABLE_LTO "Compile with Link Time Optimization (gcc and clang only)" ${LTO_DEFAULT})
+
 option( ENABLE_GBA_LOGGING "Enable extended GBA logging" ON )
 if( ENABLE_GBA_LOGGING )
    ADD_DEFINITIONS (-DGBA_LOGGING )
@@ -138,9 +150,7 @@ IF(APPLE)
 ENDIF(APPLE)
 
 # We do not support amd64 asm yet
-IF((ENABLE_ASM_CORE OR ENABLE_ASM_SCALERS OR ENABLE_MMX)
-   AND CMAKE_SYSTEM_PROCESSOR MATCHES "[xX]86|[aA][mM][dD]64|[xX]64"
-   AND CMAKE_C_SIZEOF_DATA_PTR EQUAL 8)
+IF(AMD64 AND (ENABLE_ASM_CORE OR ENABLE_ASM_SCALERS OR ENABLE_MMX))
     MESSAGE(FATAL_ERROR "The options ASM_CORE, ASM_SCALERS and MMX are not supported on AMD64 yet.")
 ENDIF()
 
@@ -291,11 +301,14 @@ ENDIF()
 # Compiler flags
 
 IF(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-    IF(CMAKE_COMPILER_IS_GNUCXX)
-        SET(LTO_FLAG -flto=10)
-    ELSE()
-        SET(LTO_FLAG -flto)
-    ENDIF()
+    SET(LTO_FLAG "")
+    IF(ENABLE_LTO)
+        IF(CMAKE_COMPILER_IS_GNUCXX)
+            SET(LTO_FLAG -flto=10)
+        ELSE()
+            SET(LTO_FLAG -flto)
+        ENDIF()
+    ENDIF(ENABLE_LTO)
 
     # common optimization flags
     SET(MY_C_AND_CXX_OPT_FLAGS -O2 -mtune=generic -fomit-frame-pointer ${LTO_FLAG})
@@ -385,7 +398,7 @@ ELSEIF("${CMAKE_SYSTEM}" MATCHES "Linux")
     ADD_DEFINITIONS(-DELF)
 ENDIF()
 
-IF(CMAKE_SYSTEM_PROCESSOR MATCHES "[xX]86|[aA][mM][dD]64|[xX]64" AND CMAKE_C_SIZEOF_DATA_PTR EQUAL 8)
+IF(AMD64)
     ADD_DEFINITIONS(-D__AMD64__)
 ENDIF()