diff --git a/src/preferences/cpufrequency/CPUFrequencyView.h b/src/preferences/cpufrequency/CPUFrequencyView.h
index 2a73932a6b..1d9a164ab9 100644
--- a/src/preferences/cpufrequency/CPUFrequencyView.h
+++ b/src/preferences/cpufrequency/CPUFrequencyView.h
@@ -32,6 +32,14 @@ enum stepping_mode {
 
 struct freq_preferences
 {
+	bool IsEqual(const freq_preferences& prefs) {
+		if (mode == prefs.mode && custom_stepping == prefs.custom_stepping
+			&& stepping_threshold == prefs.stepping_threshold
+			&& integration_time == prefs.integration_time)
+			return true;
+		return false;
+	}
+
 	// stepping mode
 	stepping_mode	mode;
 	int16			custom_stepping;
diff --git a/src/preferences/cpufrequency/PreferencesWindow.h b/src/preferences/cpufrequency/PreferencesWindow.h
index 9b33bf8f24..e903c09821 100644
--- a/src/preferences/cpufrequency/PreferencesWindow.h
+++ b/src/preferences/cpufrequency/PreferencesWindow.h
@@ -63,6 +63,9 @@ public:
 			BString&			PreferencesFile() {	return fPreferencesFile; }
 			status_t			GetPreferencesPath(BPath &path);
 
+			bool				DefaultsSet();
+			bool				StartPrefsSet();
+
 private:
 			BString				fPreferencesFile;
 
@@ -107,6 +110,7 @@ public:
 
 private:
 			void				_MoveToPosition();
+			void				_UpdateButtons();
 
 			BView*				fPreferencesView;
 			BButton*			fRevertButton;
@@ -234,6 +238,22 @@ PreferencesStorage<Preferences>::SavePreferences()
 }
 
 
+template<typename Preferences>
+bool
+PreferencesStorage<Preferences>::DefaultsSet()
+{
+	return fPreferences.IsEqual(fDefaultPreferences);
+}
+
+
+template<typename Preferences>
+bool
+PreferencesStorage<Preferences>::StartPrefsSet()
+{
+	return fPreferences.IsEqual(fStartPreferences);
+}
+
+
 template<typename Preferences>
 PrefFileWatcher<Preferences>::PrefFileWatcher(
 	PreferencesStorage<Preferences>* storage, BHandler* target)
@@ -343,10 +363,11 @@ PreferencesWindow<Preferences>::PreferencesWindow(const char* title,
 	fRevertButton = new BButton(B_TRANSLATE("Revert"),
 		new BMessage(kRevertMsg));
 
-	fRevertButton->SetEnabled(false);
 	buttonView->AddChild(fRevertButton);
 	buttonView->GetLayout()->AddItem(BSpaceLayoutItem::CreateGlue());
 
+	_UpdateButtons();
+
 	SetLayout(new BGroupLayout(B_VERTICAL));
 	fRootLayout = new BGroupLayout(B_VERTICAL);
 	fRootLayout->SetInsets(10, 10, 10, 10);
@@ -377,19 +398,19 @@ PreferencesWindow<Preferences>::MessageReceived(BMessage *msg)
 	switch(msg->what)
 	{
 		case kConfigChangedMsg:
-			fRevertButton->SetEnabled(true);
+			_UpdateButtons();
 			break;
 
 		case kDefaultMsg:
 			PreferencesStorage<Preferences>::Defaults();
-			fRevertButton->SetEnabled(true);
+			_UpdateButtons();
 			if (fPreferencesView)
 				PostMessage(kDefaultMsg, fPreferencesView);
 			break;
 
 		case kRevertMsg:
 			PreferencesStorage<Preferences>::Revert();
-			fRevertButton->SetEnabled(false);
+			_UpdateButtons();
 			if (fPreferencesView)
 				PostMessage(kRevertMsg, fPreferencesView);
 			break;
@@ -442,6 +463,22 @@ PreferencesWindow<Preferences>::_MoveToPosition()
 	MoveTo(position);
 }
 
+
+template<typename Preferences>
+void
+PreferencesWindow<Preferences>::_UpdateButtons()
+{
+	if (!PreferencesStorage<Preferences>::DefaultsSet())
+		fDefaultButton->SetEnabled(true);
+	else
+		fDefaultButton->SetEnabled(false);
+	if (!PreferencesStorage<Preferences>::StartPrefsSet())
+		fRevertButton->SetEnabled(true);
+	else
+		fRevertButton->SetEnabled(false);
+}
+
+
 #undef B_TRANSLATE_CONTEXT
 
 #endif	// PREFERENCES_WINDOW_h