Single front fan - thoughts

[eqc.liu]

Hey guys, I have a question about fans, fan ducts, and fan directions that I was hoping someone can shed some light on.

My current setup has 1 fan in the front (Noctua 140mm PWM). There are no other fans in my entire system (passive heatsinks and pico PSU). The system is running fine, ~50C CPU and 55C GPU during gaming at 27C ambient (realistically the hottest it'll be in my house as I have AC). I'm using a Lian Li PC-TU200 case with an AMD APU and GTX 750 TI graphics card.

I am in the process of seeing if I can improve the fan sound quality during gaming. Here are the setups I have in mind:

1) Front 140mm intake mounted flush - I had this set up for many months and it yielded ~50C CPU and 55C GPU during gaming. However the fan made an annoying high pitch whining sound when ramped up to 1000 rpm during gaming.

2) Front 140mm exhaust mounted flush - I tried this set up yesterday. It yielded 50C CPU and 60C GPU during gaming with the same fan profile as scenario 1. however, the sound quality was better than the scenario 1. Instead of whining it's whooshing quietly now. The front grill, however, seems very restrictive and does not let air flow freely out. It does feel good though to know that hot air is being exhausted out of my case.

3) Front 140mm intake with fan duct - I want to try this setup this weekend. I'm planning to get some long machine bolts and nuts and mount my front fan recessed from the front panel by a few inches. I'll then use ducktape and create a duct for the fan. My hypothesis is that if I move the front fan away from the intake it'll be quieter and cause less turbulence. Thoughts?

4) Front 140mm exhaust with fan duct - I'm not sure if this will work well at all...probably won't even try it.

5) Front 180mm AP182 intake with fan duct - Obviously I'll need some sort of adapter/duct to be able to use a 180mm fan on a 140mm intake. It might yield better results as I would be running a larger fan at lower rpms closer to the heatsinks. I might give this a try eventually. Also I'm hoping that Noctua will release a 180mm fan soon.

Any thoughts and input is welcomed! Attached is a picture of the internals of my rig. I'll post back results and pictures as I work on this project!

[Arbutus]

I suggest trying option 4. The air is quite turbulent coming off of the fan blades. A duct the width of your roll of duct tape will allow the turbulence to moderate before hitting the grill.

[eqc.liu]

I suggest trying option 4. The air is quite turbulent coming off of the fan blades. A duct the width of your roll of duct tape will allow the turbulence to moderate before hitting the grill.

Hm interesting. I thought it wouldn't have enough pressure to push air out through the restrictive front grill this way, but it's worth a try!

[xan_user]

here's what I would try

[eqc.liu]

Blowing into the case, yes?

[Arbutus]

I suggest trying option 4. The air is quite turbulent coming off of the fan blades. A duct the width of your roll of duct tape will allow the turbulence to moderate before hitting the grill.

Hm interesting. I thought it wouldn't have enough pressure to push air out through the restrictive front grill this way, but it's worth a try!

The grill will impede air flow, but not as much as some think. Air is a fluid and will speed up travelling through the grill and then slow down after passing through. Load testing will give you the numbers to compare with your other configurations.

Reducing the turbulence will improve the noise factor.

[xan_user]

Blowing into the case, yes?

yes.
I doubt you will see much of a temp change in any of the configs. but putting the fan as far inside the case as possible, has generally worked well for me, especially noise wise.

[eqc.liu]

Thanks for the info guys! I'll get around to doing this eventually...but right now spending a lot of time fixing up my Jeep. She's got some frame rot going on underneith .