diff --git a/indra/newview/app_settings/settings.xml b/indra/newview/app_settings/settings.xml
index 455bddf52c..a1eaa8693d 100644
--- a/indra/newview/app_settings/settings.xml
+++ b/indra/newview/app_settings/settings.xml
@@ -102,6 +102,17 @@
     <key>Value</key>
     <integer>0</integer>
   </map>
+  <key>PhoenixKeepUnpackedCacheFiles</key>
+  <map>
+    <key>Comment</key>
+    <string>If TRUE, the viewer won't delete unpacked cache files when logging out (improves overall performance and fixes sound bugs)</string>
+    <key>Persist</key>
+    <integer>1</integer>
+    <key>Type</key>
+    <string>Boolean</string>
+    <key>Value</key>
+    <integer>0</integer>
+  </map>
   <key>RadarAlertChannel</key>
     <map>
       <key>Comment</key>
diff --git a/indra/newview/llappviewer.cpp b/indra/newview/llappviewer.cpp
index bc826fcf80..384739f7ca 100644
--- a/indra/newview/llappviewer.cpp
+++ b/indra/newview/llappviewer.cpp
@@ -1529,7 +1529,10 @@ bool LLAppViewer::cleanup()
 	removeCacheFiles("*.tmp");
 	removeCacheFiles("*.lso");
 	removeCacheFiles("*.out");
-	removeCacheFiles("*.dsf");
+	if(!gSavedSettings.getBOOL("PhoenixKeepUnpackedCacheFiles"))
+	{
+		removeCacheFiles("*.dsf");
+	}
 	removeCacheFiles("*.bodypart");
 	removeCacheFiles("*.clothing");