Phanteks P400 Owners with radiator, please share your fan configuration

[bigpman]

Read a lot of posts on P400 fan configuration,but no one who has actually done some sort of testing to an optimal fan configuration.

Someone mentioned running the top 2x120 and rear 1x120 as intake with the rad up front as an exhaust for optimal positive airflow. Does this make sense?

Currently, I own 2 x stock 120mm fans and 2 x 120 Phanteks 120 static pressure fans.

Today, I am waiting for a Cooler Master Masterliquid 240 CLC to arrive and trying to figure out the best way to optimize the fans.

I am not opposed to buying new/additional fans if it makes sense. i.e. getting 2 or 3 matching airflow fans for the top and rear and just scrapping/selling the 2 static pressure ones, since I am getting 2 new cooler master fans with the AIO.

I was also thinking about taking the 2 stock fans and putting them as exhaust in the rear and top with one of the 120 SP fans at the bottom/front with the 240mm above it (the front fits 360mm all together)

I am looking for best possible positive airflow without making the case too loud, what did you do in your case?

 

[Karadjgne]

Don't own personally, but have worked/seen p400 builds. And plenty of other aio builds besides, plus a square mid-tower is pretty much all the same inside.
2 ways I've seen are like Paladins setup, that's exhaust out the front through the rad (used as pull) with top/rear intakes. That works fine, sorta, but not ideal. Imho.
My setup is similar but opposite, the 2x 140mm as intake through the front mounted rad (in push) and 2x 140mm as top exhaust, no rear. Heat rises, especially pushed by the side exhaust of the gpu, so top mounted fans make more sense than a rear mounted fan trying to pull the heat 90° sideways. With available top fan ports, the only time a rear fan makes any sense is with a tower air cooler, since that's where the exhaust is aimed anyways.

Positive/negative pressure is pretty much a fallacy, there's just too much open venting to be of much real use other than for micro-particulate dust that's local to the openings. Air pressure at sea level is 14.7 psi, with a positive system you'd be looking at 14.7001 psi, with a negative system, 14.6999 psi. That's enough to vacate local dust/smoke etc but that's about it. To achieve that requires not much more than a few changes, if using 4 identical fans the intakes run 100-200 rpm higher than exhaust fans. Or use 2x 140mm intakes at a similar rpm to 2x 120mm exhaust. All you need is slightly more cfm in than out, the radiator won't change that (contrary to popular belief) air is air, the rad only changing the pressure of exhaust not the amount of air.
So either way works, just as long as you adjust fan curves and/or fan specs accordingly.

 

[Kasper Jorgensen]

I have a 2x140mm Rad in front as intake with pull configuration, a 140mm fan at bottom as intake to supply cold air to GPU and a 140mm fan at rear as exhaust. I'm not using any top mounted fans cause i wanna avoid all the dust that will always come with a top mounted fan.

 

[leigh76]

I have the Enthoo Primo, but daaaaamn that's a sexy little case there!

 

[bigpman]

I ended up doing the following, or basically what @Karadjgne recommended.

Rad up front with fans pulling air in
An extra fan below them, with intake pulling air on to the hard drive
The 2 stock fans up to as exhaust

I also ended up mounting the additional SP fan I have at the back as exhaust, but currently I have it turned off unless temps go through the roof.

Didn't have a chance to do any stress testing yet, but idle temps on the package are currently at 29C, which is heck of a lot better than the 38-40C they were before the CLC was in there with the Hyper 212 EVO. I will also need to retake the idle temps after I let the PC run for a few hours, so that I can let the liquid equalize in temp.

Thanks everyone for responding

@leigh76, I do definitely like the case!

 

[bigpman]

The front cover on this thing is a major downfall.

Prime95, at 3.9Ghz, with front cover on, hit 75C and I stopped the test 2 minutes into it.

Without cover, for 20 minutes, max temps at 67C.

I think it's time to mod the front cover and add in some mesh.

 

[Karadjgne]

I7-3770K @4.6GHz 1.28v, Prime95 v26.6 small fft on nzxt Kraken X61 in fractal design R5 with door closed, front mount aio under pull fans (mounted inside.) ½ hr test 72°C. Gaming loads 54°C. Idle 32°C. Max speed on fans capped at 900rpm, run in silent mode, not performance.

With fans, orientation and speeds can make a difference. If you generally run the fans below 1200rpm, its better to run them pull, you get more cfm per rpm through the rad. If you run the fans generally at 1500rpm or higher, it's better to use push, where you get better cfm per rpm. If you run the fans 1200-1500 orientation makes no difference. There's a 2-3° difference from norm, both ways, so at 900rpm pull the cpu will run @4-6° cooler than at 900rpm push, or at 1700rpm push is 4-6° cooler than pull.

So thinking about your orientation, if you are running push, at idle-gaming loads, you'll run slightly hotter than norm, at max speeds (1500rpm+) you'll show cooler than norm. If running pull at gaming loads, you'll be cooler than norm, but stress tests will be slightly warmer than norm.

Also take into consideration how a fan works. It's backwards to popular belief. When the blades spin, the curvature and pitch cut through the air creating a vacuum. The byproduct of the creation of vacuum is the exhaust air you feel from the back of the fan. The higher the rpm, the stronger the vacuum. Use 2x fans running max speed, and thats a considerable amount of vacuum created under that cover, more than the venting will handle, so there's less exhaust, cpu temps at stress test loads are higher. At lower speeds, the vacuum is lower, so there's probably plenty of airspace to fill the void, so temps are nominal.

Before hacking up the case cover, run a gaming benchmark, game single player for ½ an hour. Monitor/log temps. Let the pc rest for 2+ hrs to let liquid temps acclimatize. Then run the exact same single player for another ½ an hour without the cover. See how the temps compare under gaming loads. That's a realistic test. Stress testing isn't really valid as you never hit that load unless running production apps like cpu rendering, and any version of p95 higher than 26.6 uses unrealistic instruction sets like AVX and others that'll bounce temps higher than normal usage needs. Games really don't use much, if any, AVX. That's been an issue since Haswell cpus with p95.