P400S Airflow Help

[jimmy123032]

I have a Phantek P400S and have all the fans slot filled. 1 exhaust on the back, 2 exhaust on the top, 3 intake in the front. The front intake fans only suck in air from 2 small vents because that is how the cover is designed so it isnt sucking much air in. For the two exhaust fans on top I have one towards the middle of the pc and one towards the back. The one in the back is right on top of cpu and gpu directly under the cpu. I have 2 magnetic covers for the both of the exhaust fans on top so I can cover them up if I want to. What I notice when I have both vents off is that the middle exhaust blows out cold air while the back one (I am talking about the top fan not the back back fan) blows out warm air. If I only cover the middle exhaust the back one blows hot air. I understand that I shouldnt leave hot air in my pc but should is it really better to blow out the cold air before it is even done circulating inside? Which vent should I cover for optimal temp and air flow? Should I let the middle exhaust blow out cold air or should I leave all the hot air cooped up until it goes out the back exhaust because I dont want to waste what limited air intake I have.

 

[madmatt30]

The top front exhaust I personally wouldn't have a fan in there , you're just pulling cool air straight from the case before your cpu cooler gets a chance do use it.