According to some crafty users on the NeoGAF forums, there’s an undocumented feature in the latest Xbox 360 dashboard update - a cache clear. The instructions are listed from the post below

Go to the system blade and then memory. Press Y on either the HDD or a MU and then press X, X, Left Bumper, Right Bumper, X, X. Once you do this a blade will pop up saying: This will perform maintenance on your Xbox 360 storage devices. Do you want to continue? Pick yes or no.

Of course, Microsoft officially wants you to use this option only when instructed by technical support, so proceed at your own risk. Users on the NeoGAF forum suggest that this may help to fix load time issues that have been encountered by folks after playing many games or playing games that load lots of info to the cache (Oblivion, for one). After clearing your cache and re-running a game, you might notice quicker load times. Best of luck, if you decide to try it.

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