Shared folders always accessible one way, go to sleep the other

I have two machines on Windows 8 x64. One runs headless and 24/7 just for downloads and has a new Intel ethernet card while my PC uses on-board. For some reason the rdp connection is always available to me, but if a couple hours or sometimes just a while should pass without me accessing the remote PC through shared folders, I'm hit with a not available message. The process for re-initiating them is to open the remote session, access my PC's shared folders (which are always instantly available, I wish it were the other way around) and wait 2 minutes. Lather, rinse, repeat. I double checked and none of my hdds are set to sleep, nor would they have time to and the power settings are all in place. What can I change so I have constant sharing availability? Nothing else about these connections seems spotty.