diff --git a/Source/cmGlobalVisualStudio8Generator.cxx b/Source/cmGlobalVisualStudio8Generator.cxx
index c4de91efc..2612a08b2 100644
--- a/Source/cmGlobalVisualStudio8Generator.cxx
+++ b/Source/cmGlobalVisualStudio8Generator.cxx
@@ -21,6 +21,7 @@ cmGlobalVisualStudio8Generator::cmGlobalVisualStudio8Generator()
 {
   this->FindMakeProgramFile = "CMakeVS8FindMake.cmake";
   this->ProjectConfigurationSectionName = "ProjectConfigurationPlatforms";
+  this->ArchitectureId = "X86";
 }
 
 //----------------------------------------------------------------------------
@@ -55,8 +56,8 @@ void cmGlobalVisualStudio8Generator
 //----------------------------------------------------------------------------
 void cmGlobalVisualStudio8Generator::AddPlatformDefinitions(cmMakefile* mf)
 {
-  mf->AddDefinition("MSVC_C_ARCHITECTURE_ID", "X86");
-  mf->AddDefinition("MSVC_CXX_ARCHITECTURE_ID", "X86");
+  mf->AddDefinition("MSVC_C_ARCHITECTURE_ID", this->ArchitectureId);
+  mf->AddDefinition("MSVC_CXX_ARCHITECTURE_ID", this->ArchitectureId);
   mf->AddDefinition("MSVC80", "1");
 }
 
diff --git a/Source/cmGlobalVisualStudio8Generator.h b/Source/cmGlobalVisualStudio8Generator.h
index ceee53bcc..e0d5d8044 100644
--- a/Source/cmGlobalVisualStudio8Generator.h
+++ b/Source/cmGlobalVisualStudio8Generator.h
@@ -78,5 +78,7 @@ protected:
   virtual void WriteProjectConfigurations(std::ostream& fout,
                                           const char* name,
                                           bool partOfDefaultBuild);
+
+  const char* ArchitectureId;
 };
 #endif
diff --git a/Source/cmGlobalVisualStudio8Win64Generator.cxx b/Source/cmGlobalVisualStudio8Win64Generator.cxx
index ea2c65f3a..3469b1710 100644
--- a/Source/cmGlobalVisualStudio8Win64Generator.cxx
+++ b/Source/cmGlobalVisualStudio8Win64Generator.cxx
@@ -19,6 +19,7 @@
 
 cmGlobalVisualStudio8Win64Generator::cmGlobalVisualStudio8Win64Generator()
 {
+  this->ArchitectureId = "x64";
 }
 
 ///! Create a local generator appropriate to this Global Generator
@@ -47,6 +48,4 @@ void cmGlobalVisualStudio8Win64Generator
 {
   this->cmGlobalVisualStudio8Generator::AddPlatformDefinitions(mf);
   mf->AddDefinition("CMAKE_FORCE_WIN64", "TRUE");
-  mf->AddDefinition("MSVC_C_ARCHITECTURE_ID", "x64");
-  mf->AddDefinition("MSVC_CXX_ARCHITECTURE_ID", "x64");
 }
diff --git a/Source/cmGlobalVisualStudio9Generator.cxx b/Source/cmGlobalVisualStudio9Generator.cxx
index 98acf0f89..f8ceea0b0 100644
--- a/Source/cmGlobalVisualStudio9Generator.cxx
+++ b/Source/cmGlobalVisualStudio9Generator.cxx
@@ -25,8 +25,8 @@ cmGlobalVisualStudio9Generator::cmGlobalVisualStudio9Generator()
 //----------------------------------------------------------------------------
 void cmGlobalVisualStudio9Generator::AddPlatformDefinitions(cmMakefile* mf)
 {
-  mf->AddDefinition("MSVC_C_ARCHITECTURE_ID", "X86");
-  mf->AddDefinition("MSVC_CXX_ARCHITECTURE_ID", "X86");
+  mf->AddDefinition("MSVC_C_ARCHITECTURE_ID", this->ArchitectureId);
+  mf->AddDefinition("MSVC_CXX_ARCHITECTURE_ID", this->ArchitectureId);
   mf->AddDefinition("MSVC90", "1");
 }
 
diff --git a/Source/cmGlobalVisualStudio9Win64Generator.cxx b/Source/cmGlobalVisualStudio9Win64Generator.cxx
index 67c0bf612..ff4fd4f5d 100644
--- a/Source/cmGlobalVisualStudio9Win64Generator.cxx
+++ b/Source/cmGlobalVisualStudio9Win64Generator.cxx
@@ -16,6 +16,7 @@
 
 cmGlobalVisualStudio9Win64Generator::cmGlobalVisualStudio9Win64Generator()
 {
+  this->ArchitectureId = "x64";
 }
 
 ///! Create a local generator appropriate to this Global Generator
@@ -44,6 +45,4 @@ void cmGlobalVisualStudio9Win64Generator
 {
   cmGlobalVisualStudio9Generator::AddPlatformDefinitions(mf);
   mf->AddDefinition("CMAKE_FORCE_WIN64", "TRUE");
-  mf->AddDefinition("MSVC_C_ARCHITECTURE_ID", "x64");
-  mf->AddDefinition("MSVC_CXX_ARCHITECTURE_ID", "x64");
 }