That could work semi decently but you will need to use Quicksync as your encoder because h264, even though its much better, it will tax your cpu too much and you wont be able to stream while playing.
With your current setup, try using NVENC as your encoder as I believe the 750ti supports it, that will take some strain off your cpu and will use your gpu for encoding. Worth a try and if it works well for you then you can save some money for a better upgrade in the future