Good Idea? flipping the PSU fan to act as intake fan?

Hey guys, it's been awhile since i was last logged back no [H].
Anyawys, I have a little question whether it is a good idea or not.
Currently I am trying to build a silent mini ITX build however I have a little issue with the northbridge. ( the temp is way too high, 80C when i m watching some movies with it )
I thought it was the northbridge heatsink not sitting probably ( you know how easy to knock over or make it wobbling ), so I reseat the northbridge heatsink, but the problem is still exist. Here is one problem, I don't remember it well but I don't think the northbridge was that hot before i change my CPU heatsink. I don't know if this is one of the reason why this thing run a little hot, beacuse I am trying to run everything passive beside the PSU. Here is the list of component I am using with this mini ITX build.

Case: Lian Li PC-Q07B
PSU: Corsair HX620 with Thermalright 1300RPM fan
Mobo: Zotac GF9300-ITX WiFi
CPU: Intel Q9450 with Thermalright AXP-140 fanless
RAM: Kingston HyperX CL4 DDR1066 2x2GB
HDD: Western Digital 6400AKKS
ODD: Lite-On DVD Writer

Even tho some of the stuff seems overkill ( such as the HX620 and the Q9450 ), but those are some stuff I have from the previous rig. Anyways the problem is here now. My guess is that the TR 1300RPM fan that act as the exhaust fan for the whole system is not powerful to pushes the air out of the system, not only that, it also causes the PSU running a little hotter than before. Right now I am thinking, should I use the Scythe Kama-Flex 1900RPM fan ( an extra one ) and flip it inside the PSU and use it as a intake fan to cool down both the PSU and northbridge. ( more like cooling the CPU, but would the AXP-140 blocking the "fresh cold" air to the northbridge ) I really dont think 35DBA will be too audible, compare to the 1300RPM which was absolutely quiet. My first concern is cooling the northbridge, because having it at 80C is really not a good idea right? and second would be the PSU, since there is no temp sensor on it I had no idea how hot it was running. I have no problem with the CPU at all, since it is HTPC and I don't OC with it, the temp never go above 50C which i m very happy about.

I know sometimes I do stupid things, but please help me out here and please keep the flaming/bitching to the minimum, thanks!

To mods, is it ok for me to make a link in the SSF section to direct to this thread? I would like more people to help me out, thanks.

PS. sorry for posting such a long thread with poor English, hope you guys can understand! Thanks!

KeymaN

The fan inside the Corsair PSU is already an intake fan.

It would be more helpful to know what your case fans are. You can switch the fans on your PSU but that unit is not recommended to be used for making the case cooler. The reason why is that the PSU gets hot, so any air that comes out of it will be hotter than ambient.

What I would do is examine the stock fans used in your casing and see if you can replace them with higher airflow fans. Also if there are any optional fan mountings, install additional fans there. That will get your case much cooler than attempting to use your PSU to vent warmed air into the case.

Thanks for the fast response Danny. ( as usual )
I just want to clarify one thing, what I mean by intake fan is having the PSU fan taking fresh air outside of the case into the chassis, not having the air inside the chassis going out of the PSU. From my understanding is that, the original setting for the PSU fan was having the air inside the chassis going outside of the case. But what I want to do right now is to have the fan taking air into the chassis. First of all the low ( 1300 ) RPM fan that was sucking the air out of the chassis is not powerful enough, plus it actually drawing more hot air into the PSU itself. So that is why i want a higher speed ( 1900RPM ) fan to draw the air from the outside into the case, not only it will cool down the PSU but possibly cooling the northbridge too.
I might be wrong but just need to double check/clarifing it.

With the Lian Li PC-Q07B, there is no case fans or fan mounts since it was designed for mini ITX or HTPC build. What bothered me the most was only the northbridge temp. Beacuse of the hotness ( 80C ) from the northbridge, it is the reason causing the PSU to get warmer/hotter. ( because the PSU is sucking those heat from inside the chassis )
Also one thing is the room that this rig is sitting usually have a low ambient temp, even when it was summer time. Since fall is already here, the room is always chilly plus i never close my window and the window is pretty close where the rig is sitting too.
Hope that would help you guys better with more info.

KeymaN said:

Thanks for the fast response Danny. ( as usual )
I just want to clarify one thing, what I mean by intake fan is having the PSU fan taking fresh air outside of the case into the chassis, not having the air inside the chassis going out of the PSU.

Click to expand...

Bad idea. The insides of a PSU is hot. You don't want air FROM the PSU getting into the PC itself. It will not cool down the PC at all. Besides, it does not matter if the PSU is a little hotter than before. The Corsair is more than capable of handling extra heat.

The only real problem you have is the northbridge. Maybe try an aftermarket heatsink for it?

add a aftermarket cooler on northbridge one with a fan on it , that is best solution . i have done same to my 9300 and temps havent exceeded 65c sinc


Jen

So should i try a faster fan right now to see if anything improve? if not i should try an aftermarket northbridge heatsink? any suggestion on that and is there a way to make sure it is secure to mount on the northbridge? it is really troublesome how northbridge heatsink never sit tight on the northbridge. and how do i know if the PSU is too hot? cuz it was a quite hot when i try to touch the PSU.

Thanks a ton!

KeymaN

Hey Jen, would you recommend me any northbridge heatsink with fan? or can you tell me which one you are using right now? and I would like to know if those fan make any noises. ( sorry for being a pain in the ass )

KeymaN said:

So should i try a faster fan right now to see if anything improve? if not i should try an aftermarket northbridge heatsink? any suggestion on that and is there a way to make sure it is secure to mount on the northbridge? it is really troublesome how northbridge heatsink never sit tight on the northbridge. and how do i know if the PSU is too hot? cuz it was a quite hot when i try to touch the PSU.

Thanks a ton!

KeymaN

Click to expand...

You'll know when the PSU is too hot when you start having stability problems or use temperature gauge to monitor the exhaust coming from the PSU. But remember that the Corsair PSUs are rated for 50C usage.

Faster fan inside the PSU itself? No. The fan speed is controlled by the onboard controller. So you'll probably end getting the same amount of airflow.

I see, thanks for the tips Danny.
So it doesn't matter what speed the fans are right? either a 1300 and 1900 fan? they can still be controlled into different speed? letz say they will both go down to 1000 or even 2000 when needed?

KeymaN said:

I see, thanks for the tips Danny.
So it doesn't matter what speed the fans are right? either a 1300 and 1900 fan? they can still be controlled into different speed? letz say they will both go down to 1000 or even 2000 when needed?

Click to expand...

Basically doesn't matter what the speeds since the PSU will be controlling the speeds of the fan depending on the internal temperature of the PSU. So whether or not you have a 1300 or 1900 fan, it'll be set to the same speed.

i personally wouldn't mess with the psu fans......
besides it is better to have the hot air going out rather than in.....

here are some ideas.

1. inflow=outflow example. three fans blow air into the case and three fans blow hot air out of the case.

2. draw air in from one end of the case and have hot air blown out the other end of the case..... example. the psu is in the back to have all the fans on the back of the case blow hot air out as well, conversely use the front to draw cooler air in.

3. you mentioned that northbridge temps where not an issue before the install of a new cpu heatsink.... i am willing to bet the new cpu heatsink is either blowing hot air onto the northbridge or blocking convection preventing circulation..... if that is the case the problem can be fix'd.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835116018
or something like the item link'd,,,, shop around and see what will work best....