This thread is long but there is some good information in it.
https://bitcointalk.org/index.php?topic=140539.0One thing you can look for and this is at your own risk.
In the control panel go into cgminer configuration. In there is usually a "Chip Frequency" box. It is most likely set to default. You can carefully choose the next step up reboot and run for a few hours and see how it goes. It should increase your hash rate. If not or you get lots of errors you might not have it cooled properly or it may need a larger PSU.
If it works well after 2 to 3 hours you can try the next setting up and repeat the process.
Make sure you have it in an area that is nice an cool so it does not overheat.
Not all of them can overclock though so keep that in mind.
I used the reset switch and now I'm online hashing at 39-40GH/s. Can you recommend any good documentation on tweaking the Mini to get that hashrate up?