This is what I am trying to accomplish with the power settings. It's a link for power settings for a Surface Pro 1 & 2, but I would think the 3 would be similar.
All That Nerdy Stuff
I went into my power options to change some of the advanced settings and most of them are missing? I am on windows 8.1 with a week old Surface Pro 3. I want to say I read somewhere that hyper-v can cause options to be missing, but I honestly don't even know what that is and I don't have it...