Fan setup - Don't want negative pressure

[Will Ozellman]

Okay so i'm finalizing my first build tonight or tomorrow. I'm building in a H440 and here is my current setup.

 

Front intake: 3x120 noctua silent series running with the low noise adapter (900 rpm)

Back exhaust: stock 140 mm fan that came with the case

Top exhaust: 140 mm Noctua redux PWM 1500 RPM (this will combine with my kraken x41)

 

EDIT: Okay for some reason half my post didnt save. I now see your confusion.

 

So what i was gonna ask was do i actually need the two exhausts or should i just move the noctua fan and the kraken to the back slot and skip the top fan all together?

 

My goal is to build a very silent pc that is also functional for light overclocking (no volt increases)

[intelCore]

What are you gonna be cooling with this?

[SaladFingers]

You really don't need that top exhaust. The case fan on the back is more than enough to get the air flow going and keeping just that ensures you a positive pressure. The only case I would personally use the top slots is for a radiator, and even that I found that it was working better as intake on my build (yes, the hot air goes up etc, but really this effect can be countered with like, 100rpm on the fan). In theory with your setup you will still achieve positive pressure if you don't run the exhaust fans too high. but yeah, I'd say lose the top fans if you're not putting a rad up there. Just my 5C anyway.

[jaffacakes]

Okay so i'm finalizing my first build tonight or tomorrow. I'm building in a H440 and here is my current setup.

 

Front intake: 3x120 noctua silent series running with the low noise adapter (900 rpm)

Back exhaust: stock 140 mm fan that came with the case

Top exhaust: 140 m

 

Addition the CFM from the intake fans minus the CFM of the two fans, if the result is positive, then there's positive airflow, if negative negative airflow. 

[Will Ozellman]

What are you gonna be cooling with this?

i7-4790k

gtx 980 ti 

16 gb ddr3

1 ssd 1 hdd

[Will Ozellman]

You really don't need that top exhaust. The case fan on the back is more than enough to get the air flow going and keeping just that ensures you a positive pressure. The only case I would personally use the top slots is for a radiator, and even that I found that it was working better as intake on my build (yes, the hot air goes up etc, but really this effect can be countered with like, 100rpm on the fan). In theory with your setup you will still achieve positive pressure if you don't run the exhaust fans too high. but yeah, I'd say lose the top fans if you're not putting a rad up there. Just my 5C anyway.

Well i am having a radiator at the top exhaust but i see many ppl having their radiator at the back aswell without top fans.

 

EDIT: half my post didnt save for some reason so i edited the original post.

[Will Ozellman]

Addition the CFM from the intake fans minus the CFM of the two fans, if the result is positive, then there's positive airflow, if negative negative airflow. 

Well im kinda new to this and the pwm fan will run at different speeds depending on how hot the cpu gets. also, i hear you gotta account for the gpu blowing out air aswell. The gpu will of course also vary in fan speed so i dont know how i should count it out.

[jaffacakes]

Well im kinda new to this and the pwm fan will run at different speeds depending on how hot the cpu gets. also, i hear you gotta account for the gpu blowing out air aswell. The gpu will of course also vary in fan speed so i dont know how i should count it out.

 

Yes, but that gives you an idea about it being positive or negative airflow. 3x 120 fans vs 2x 140 fans should be enough.

[intelCore]

i7-4790k

gtx 980 ti 

16 gb ddr3

1 ssd 1 hdd

I'd put it in and see how it sounds and performs. If you find it too loud take it out and look at how the tempretures change if they do. Airpressure should be positive either way.

[SaladFingers]

Is that a single rad or a 280mm one? Asking because you mentioned two 140mm fans for it. If so, then yes the top is a great place to put it. Please do yourself a favor and try both intake and exhaust though. Everyone keeps repeating the "back/top should ALWAYS be exhaust" nonsense. On my build, exhaust meant my CPU would run about 3-4 degrees hotter, while turning it to intake I didn't even see a 1 degree deference in the rest of the parts.

 

edit: Though if your GPU isn't 'open air' type, you shouldn't notice much difference anyway.

[Will Ozellman]

Is that a single rad or a 280mm one? Asking because you mentioned two 140mm fans for it. If so, then yes the top is a great place to put it. Please do yourself a favor and try both intake and exhaust though. Everyone keeps repeating the "back/top should ALWAYS be exhaust" nonsense. On my build, exhaust meant my CPU would run about 3-4 degrees hotter, while turning it to intake I didn't even see a 1 degree deference in the rest of the parts.

 

edit: Though if your GPU isn't 'open air' type, you shouldn't notice much difference anyway.

 

 

It's a single 140 radiator. I got the noctua fan specifically for this but didnt bother to change the actual rear fan mosty because its hard to find 140 fans with good airflow that is also quiet.

 

If i go with 3x120 + 1x140 mm intake it would be overpowering the single 140 mm out no?

 

as for my gpu, it will probably be the msi gaming 980 ti with the twinfrozer cooler.

[SaladFingers]

It's a single 140 radiator. I got the noctua fan specifically for this but didnt bother to change the actual rear fan mosty because its hard to find 140 fans with good airflow that is also quiet.

 

If i go with 3x120 + 1x140 mm intake it would be overpowering the single 140 mm out no?

 

as for my gpu, it will probably be the msi gaming 980 ti with the twinfrozer cooler.

 

 

It would not, because computer cases are well ventilated. Any extra air coming in that can't be picked up by the exhaust fan, will simply push its way out from all the holes. That's what positive pressure does, generally speaking. I'd say go with your plan, and just give the CPU cooler a try in both intake and exhaust and check all of your temps. Run a test with only the CPU stressed, then with both GPU and CPU. In my case the GPU produced a lot of heat and hindered my CPU cooler's performance, which is why I turned it into intake. Some people have reported that the rest of their hardware got hotter when they used intake, but for me it didn't appear to change anything at all. Everyone's setup is a little different, so testing will be the clear answer

 

 

Edit to add: Since this is a single 140 rad, you could also try to mount it where the exhaust fan is on the back. If you got the space, maybe mount it on top of it, to turn it into a push&pull config. But again, the GPU might hinder its performance under load.