Sonata II with two Nexus fans, push or pull?

Swede2 · Post by **Swede2** » Wed Oct 05, 2005 10:38 pm

I have an Antec Sonata II with one nexus 120mm fan in the back and one in the front (connected to 7V). The CPu is cooled by a Thermalright XP-90 and a Panaflo 92mm fan.

the back Nexus is drawing air out of the case and the front is drawing it in. the front of the Antec is behind a small door (it's standing in my desk), but the back is uncovered.

I have noticed that the case temp is up around 38-40 degrees sometimes.

So now I'm thinking about maybe changing the directions of the fans. Maybe put the back Nexus to pull air into the case as well. there is a small vent hole where the ADAC is supposed to be and I was think that it might be enough for the air to escape. I was thinking about this since it seems to me that there is more cool air on the back of the computer than on the front, and also a bigger intake.

Has anyone tried to do this? Will there be more turbulence noise if the fans are put in opposite directions?

Post by **Ralf Hutter** » Thu Oct 06, 2005 6:23 am

I doubt that you'd see any cooling benefits from that alternate configuration, mostly due to trying to work against the natural tendency of the warm/hot air to rise. You'd also be fighting the PSU airflow. I'd actually expect you to end up with higher temps across the board.

Try it yourself though. It's super easy to do, and you can see what results you actually get, rather than depending on someone else's wild guessing.

~El~Jefe~ · Post by **~El~Jefe~** » Fri Oct 07, 2005 8:09 pm

it wont work that well.

best way to do a fanned psu setup is by having more push from the front fan than the rear fan is exhausting. this allows the psu fan to exhaust its own air without fighting the rear exhaust for that air.

i tried this on all of my setups and it works every time. All my setups are 24/7 types, so a slight pressure negativity eventually ends in the seasonics permanently ramping and not comming down.

matva · Post by **matva** » Mon Oct 10, 2005 4:24 pm

that is interesting. i also have a sonata II, but i only run mine with the single exhaust fan. Could this be causing my smart power 2.0 to running @ full power more than it should?

~El~Jefe~ · Post by **~El~Jefe~** » Mon Oct 10, 2005 6:37 pm

from what i have tested, yes.

I reduced my papst 120 with my seasonic 400 tornado right next to it. the outcome was that the seasonic ramped up LESS often and stayed at low for most of the day. adding a fan to the front allows for more cooling without that negative pressure effect. I guess you could say it adds positive pressure. it at least makes it neutral. I always recommend a front fan pushing more air than the rear.

negative pressure causes the exhaust to fight the cooling of the psu.

Aris · Post by **Aris** » Mon Oct 10, 2005 7:19 pm

i used to also be a firm believer in a push/pull effect. pull air in from the front, and push it out the rear through the psu. this helps even out case pressure and improve air flow patterns, but it doesnt actually increase overall case airflow (CFM)

but now that i changed out all the fans, and hard volted them down to 7volts, i decided to drop the front fan to imrpove the noise it emitted.. temps are a little higher, but fans dont ramp up because they are fixed to a set voltage. and the noise is alot less now because their is no fan right in the front of the case right where i sit.

as is now, the only reason i would ever use a front fan is to cool a hard drive, but personally id rather design the system better in a way where i didnt need to do this.

matva · Post by **matva** » Mon Oct 10, 2005 8:35 pm

welp my hdd sits at ~31c idle, case temp 34c.. I dont think i have a problem there. ive got my antec tricool sittin in the back on low setting. i think it is somethin to note that the smart power 2 is not the seasonic. From what ive seen, the seasonic has its fan pointing downward towards the cpu. the smart power2.0 has it facing towards the optical drives. Does this make any difference? From what i understand, that fan pulls air in, and spits it out on the other side.. is that correct? Anyway, i plan on upgrading to the seasonic s12 500 soon so it may be an issue. I think maybe that by running the exhaust very low, it will be less of a problem?

Swede2 · Post by **Swede2** » Wed Oct 12, 2005 10:36 am

Well, I tried it anyway.

The CPU temp went down from 45 degrees in idle to around 37. This is mainly due to the fact that the rear fan pulls in air from the back and directly on to the Thermalright xp-90. Case temp is around 40 degrees in idle.

But after reading all this, I'm thinking of maybe switching fan connections, so that the rear fan is running at 7V, pulling air out, and the front fan controlled with Speedfan, at 12V and pulling air in.

The Sonata II front fan isn't placed that good since there is around 5-6 inches between the fan and the actual intake.

More results to come.

Swede2 · Post by **Swede2** » Sun Oct 16, 2005 11:17 pm

Ok, some more changes... I'm writing this in case someone is looking into modding a Sonata II case.

I put the front fan directly onto the front panel. I used some elastic cord to tie the fan to the front (maybe I'll post pictures in the gallery later). This way the fan pulls more air in and the HD stays at 20-25oC.

the HD is now suspended with the same type of elastic cord, and WOW what a difference. A little clicking is all that is heard. I have more than once leaned down to check if the HD is actually running or not.

Case fan is now again pointed backwards since the front fan is working so good. And the ACAG "hole" in the bottom of the case is taped up (actually the plastic cover is taped up since I'm not sure that I'll keep it or not).

Next step is maybe to switch the fans in the PSU. Has anyone go any experience with the Smartpower 2.0 and replacing fans? I was thinking of Panaflos there. The PSU is now the loudest component and it is not even running at full load...

Temps at idle:
Case: around 35
MB: around 35-37
CPU: around 38-40
HD: around 20-25

Post by **Ralf Hutter** » Mon Oct 17, 2005 5:45 am

Swede2 wrote:Ok, some more changes... I'm writing this in case someone is looking into modding a Sonata II case.....blah, blah.......

~El~Jefe~ · Post by **~El~Jefe~** » Mon Oct 17, 2005 6:29 pm

how crazy odd could a sonata II be. come come now ralphie boy

Post by **Ralf Hutter** » Tue Oct 18, 2005 5:12 am

~El~Jefe~ wrote:how crazy odd could a sonata II be. come come now ralphie boy

I wanna see his front fan mounting technique. That's something that you don't see on a Sonata very often.