diff --git a/dom/base/nsDOMWindowUtils.cpp b/dom/base/nsDOMWindowUtils.cpp
index aabc07c4f3e..e761367fea1 100644
--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -655,6 +655,9 @@ nsDOMWindowUtils::GarbageCollect(nsICycleCollectorListener *aListener)
   }
 #endif
 
+  if (nsContentUtils::XPConnect()) {
+    nsContentUtils::XPConnect()->GarbageCollect();
+  }
   nsJSContext::CC(aListener);
 
   return NS_OK;
diff --git a/dom/base/nsJSEnvironment.cpp b/dom/base/nsJSEnvironment.cpp
index ef34dd48e63..ff4f32787a1 100644
--- a/dom/base/nsJSEnvironment.cpp
+++ b/dom/base/nsJSEnvironment.cpp
@@ -169,14 +169,16 @@ static PRLogModuleInfo* gJSDiagnostics;
 #define NS_MIN_CC_INTERVAL          10000 // ms
 // If previous cycle collection collected more than this number of objects,
 // the next collection will happen somewhat soon.
+// Also, if there are more than this number suspected objects, GC will be called
+// right before CC, if it wasn't called after last CC.
 #define NS_COLLECTED_OBJECTS_LIMIT  5000
 // CC will be called if GC has been called at least this number of times and
 // there are at least NS_MIN_SUSPECT_CHANGES new suspected objects.
 #define NS_MAX_GC_COUNT             5
-#define NS_MIN_SUSPECT_CHANGES      10
+#define NS_MIN_SUSPECT_CHANGES      100
 // CC will be called if there are at least NS_MAX_SUSPECT_CHANGES new suspected
 // objects.
-#define NS_MAX_SUSPECT_CHANGES      100
+#define NS_MAX_SUSPECT_CHANGES      1000
 
 // if you add statics here, add them to the list in nsJSRuntime::Startup
 
@@ -271,7 +273,7 @@ nsUserActivityObserver::Observe(nsISupports* aSubject, const char* aTopic,
     if (sUserIsActive) {
       sUserIsActive = PR_FALSE;
       if (!sGCTimer) {
-        nsJSContext::IntervalCC();
+        nsJSContext::MaybeCC(PR_FALSE);
         return NS_OK;
       }
     }
@@ -3610,6 +3612,21 @@ nsJSContext::ScriptExecuted()
   return NS_OK;
 }
 
+static inline uint32
+GetGCRunsSinceLastCC()
+{
+    // To avoid crash if nsJSRuntime is not properly initialized.
+    // See the bug 474586
+    if (!nsJSRuntime::sRuntime)
+        return 0;
+
+    // Since JS_GetGCParameter() and sSavedGCCount are unsigned, the following
+    // gives the correct result even when the GC counter wraps around
+    // UINT32_MAX since the last call to JS_GetGCParameter(). 
+    return JS_GetGCParameter(nsJSRuntime::sRuntime, JSGC_NUMBER) -
+           sSavedGCCount;
+}
+
 //static
 void
 nsJSContext::CC(nsICycleCollectorListener *aListener)
@@ -3626,7 +3643,9 @@ nsJSContext::CC(nsICycleCollectorListener *aListener)
   sCCSuspectChanges = 0;
   // nsCycleCollector_collect() no longer forces a JS garbage collection,
   // so we have to do it ourselves here.
-  if (nsContentUtils::XPConnect()) {
+  if (nsContentUtils::XPConnect() &&
+      !GetGCRunsSinceLastCC() &&
+      sCCSuspectedCount > NS_COLLECTED_OBJECTS_LIMIT) {
     nsContentUtils::XPConnect()->GarbageCollect();
   }
   sCollectedObjectsCounts = nsCycleCollector_collect(aListener);
@@ -3641,21 +3660,6 @@ nsJSContext::CC(nsICycleCollectorListener *aListener)
 #endif
 }
 
-static inline uint32
-GetGCRunsSinceLastCC()
-{
-    // To avoid crash if nsJSRuntime is not properly initialized.
-    // See the bug 474586
-    if (!nsJSRuntime::sRuntime)
-        return 0;
-
-    // Since JS_GetGCParameter() and sSavedGCCount are unsigned, the following
-    // gives the correct result even when the GC counter wraps around
-    // UINT32_MAX since the last call to JS_GetGCParameter(). 
-    return JS_GetGCParameter(nsJSRuntime::sRuntime, JSGC_NUMBER) -
-           sSavedGCCount;
-}
-
 //static
 PRBool
 nsJSContext::MaybeCC(PRBool aHigherProbability)