Antec 300 fan setup

[bkoltai9]

Hi everyone. I know this subject has been brought up many times, but its new to me and I want to share my question and thoughts.

Antec 300 comes with a 140mm top fan and 120mm rear fan. I have an asrock z68 mobo, i5-2500k with 212 evo cooler, pushing air through the fins toward the rear.

I wanted to switch to positive pressure to keep the interior cleaner, pulling all air through the front grille with two corsair sp-120 quiet edition fans. I have closed off the side intake grille.

I was testing my setup, and playing with fan speeds and settings, and I find no matter how I set it up, the top and rear fans seem to compete. They should be be expelling air, but whichever is weaker causes its expelled air to get sucked back in at the edge closest to the other fan. This seems to me counterproductive. If I remove on fan, the same thing still happens. Positive pressure expels air through the opening, but it gets sucked back in toward the running exhaust fan.

The last thing I tried before going to sleep was flipping the top fan to intake and removing the rear fan. This way all the air exits the rear of the case through the one rear fan grille (as well as rear PSU and blower Zotac gtx680). I like the idea of all the air exiting the rear, but I worry all that hot air will rise and just return through the top intake. Also that intake would need a custom fan filter or it will make the case filthy.

I'm tempted to try with both top and back fans removed so all air moves evenly out the top and rear grille's, without being sucked back in. Another option would be to close off the top completely to make a stronger expulsion force through the rear (and reduce dust settling inside when computer is off). If I did this, perhaps I'd add back the side intake to give additionalfox airflow.

Obviously, I'm a little confused and I'd love some help and recommendations. All my testing yesterday was just airflow observation and I haven't tried taking load temps with different configs, which I'll do today. Is prime95 still the goto stress test?

Thanks everyone.

 

[coozie7]

As I recall the Antec 300 has a filter in the front, you'll really need to use the AF120SP high static pressure fans (or similar) to pull a good amount of air through it.
My i5 750 rig was in a Antec 200 case and I ran it with 2x120mm AF120SP front and the stock Tricool in the rear at full speed with the top and side vents blocked (top with a book, side with some black card stuck to the inside with some tape). Despite a heavily overclocked CPU and HD7950 all was cool and the cat fur stayed out.