Need help with 120mm fan placement in case!

Okay I have an Extreme Air cooling case that will hold 13 case fans!! (Ebay is a wonderful thing) Anywho, I have two 80mm fans in front blowing in, two more in back blowing out and a 120mm Muffin fan sitting directly over the proc. Now my question is this. Should the 120mm fan blow air IN or OUT of the case? My gut says the 120 blows MAD cool air INTO the case so go that way, BUT common sense tells me that blowing that much air directly onto the hsf counteracts the air movement of the hsf and therefore decreases the overall cooling of the proc. Any ideas? The 120mm is mounted on the left side panel from the front and is directly over the hsf. I have room for TWO 120mm fans stacked on the left side panel. Should I have the one on top of the hsf blowing out while I have the one below it blowing in? Help me out guys!!!!

you generally want air being blown onto the cpu, not being sucked off it

But wouldn't that nullify the hsf?

If I blow air at the cpu doesn't that counteract the hsf? the stock hsf pulls air OFF the heat sink doesn't it?

well first, the stock hsf blows down. almost every, except an alpha, heatsink is made to be blown down upon. but still, yes it does counteract the rotation of the hsf slightly. i have a stock amd hsf and it rotates at 5000rpm. i have a 120mm fan over a hole i cut in the side of my case directly over the hsf, just as you are considering placing your fan. The fan reduces the stock hs fan to blowing at ~4800rpm, if i take the side of my case off the rpm's go back up. with the fan however it drops my full load temps atleast 5C. The added flow it creates right over the heatsink with the cool room air really helps.

BTW please dont put in 13 case fans, good lord that could be loud.

HAHAHA It's bad enough with 5!!!

Okay, so my gut feeling was right. Well, anyways this case allows for TWO 120mm fans mounted directly over the motherboard. One is directly over4 the proc. The cool thing is, the 120mm Muffin fan I'm using is independently wired for a wall outlet, so I just plug it into the Aux button on my Power/usb hub and when I want extra cooling, I hit a button and WHOOSH! With all fans on it can get a tad noisy, but I just crank the volume on my Altec Lansing Speakers and drown out the vacum cleaner! LOL If what you say is correct then I'll probably add the other one. These 120mm Muffin fans move TONS of Air, and are fairly quiet. Besides, I'd prefer a little noise to having Water ANYWHERE near my brand new motherboard!

I don't believe 13 case fans will be beneficial at all. Too many fans will disturb the air flow, cause some turbulence inside the case which will reduce the efficiency of carrying heat out. Two intakes, two blow out, plus psu and cpu fan and at most one fan at side blow to AGP. Anything more than that will be redundant.

I agree...

Thats why I am only using 5 fans currently. 2-80mm's in front 2 more in back and the one 120mm. However, I believe the case design would allow for effective cooling if all the fans were properly placed directionally. More to the point though, the noise would be unbearable. It's not bad at all with the 4 80's running, and isn't terribly disturbing with the 120 on. All in all it's a phat rig really. If I could figure out how to post an avatar on here I'd post a picture of it for everyone to see.