Even though the external cache has been enabled by default for some time, many nightly-build testers still have the registry key lying around which prevents the cache from being used.
--- trunk/NightlyBuild.txt (revision 2991)
+++ trunk/NightlyBuild.txt (revision 2992)
--- trunk/src/TortoiseProc/TortoiseProc.cpp (revision 2991)
+++ trunk/src/TortoiseProc/TortoiseProc.cpp (revision 2992)