The power supply should be sufficient at 650wattage, a lot of the time people overkill how much power they have in their system so that should be fine.
I would recommend upgrading to 8 or 16 for your ram. Will help increase your overall performance and speed.
Streaming: you'll be fine a lot of people stream on a lot worse. just make sure you have good software like xsplit.
Your over clock may have not registered by the OS try rescanning to see if it fixes. And double check in your bios that its at that frequency still.