Yes, C_D is correct.
The longer you run prime95 (up till about four hours) usually will mean you have a more stable system. It also gives you a good temp range to work with and see what you might need to do.
Why up till about four hours? It is my personal belief that, past that point, prime95 will fail at some point, but it's not because of system stability (ok, actually it is, but you're asking it to at that point). It's practically a diminishing returns kinda deal. After about four hours your temps more than likely won't be getting much higher and you might be getting a little antsy.
You're going to need more airflow in that case. It is specifically designed to be silent with limited airflow. Higher CFM Fans for the actual case would help the air flow tremendously. If and when you decide you want a tower cooler or all-in-one your going to need higher Static Pressure fans to keep 'er kool.
Also, I ain't seeing any specs. All I know is your running 83XX with a stock cooler but who knows what else. GPU? It can definitely contribute to the standing airflow in the case. You can put that stuff in the signature by going to the top of the dash board and hit "quick links". There should be an "Edit Profile" up there where you can put your rig in the sig (Ha, I'm a rhyming beast!). It should look like mine and the rest of us down below.