ReaperController has an option to restart Reaper at a defined interval. Find it here: http://www.reddit.com/r/litecoinmining/comments/1byu07/i_made_a_reaper_gui_version_try_it_out/

I needed to use it awhile ago because the drivers were crashing for some reason on the 5870 I was mining with. It's a bandaid fix for a bigger problem as others have noted.

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