This is the program most of us used in SC/Mempo to stream but you can also do direct file output. It still eats resources but not nearly as badly as when you are streaming with it.
Here's an example of me running a very lag inducing build.
I'm using the 64-bit version of the software.
Max BR: 2000
Mode = file output only
Custom = 1280 x 720
Resolution downscale = none
FPS = 30
Disable Aero = yes
Of course, you can play around with settings and see what works best for you. Also, if any part of your game screen is getting cut off, or if your scene is too big (there is extra space around the game screen); then you need to go to the "edit scene" function and adjust the frame.