I decided to disconnect about 5 cables from my motherboard to try to save some power. Do I need to disconnect both ends to stop power from being drawn or is it fine with just disconnecting one end.
The cables are still connected to the motherboard but I disconnected the cable from the USB ports/memory card readers and a DVD burner.
If there weren't any USB devices attached to the USB ports you disconnected and there were no memory cards in the memory card reader then disconnecting them will save you nothing.
Did you disconnect only the data cable to the DVD burner? That won't save you any power either. You need to disconnect its power cable. The data cable can be left attached.