How many fans can a 350W PS take?

[govtcheez75]

Ok. I was getting really crappy temps in my Antec Lanboy case...so I probably should have gotten a larger case with better airflow. Oh well, I just decided to mod it, and add a TON of fans to it, to cool this sucker down. This case came with a Antec 350 Smart Power PSU, with the blue LED. It supports 2 80mm fans, one for intake, and one for exhaust. Here are the Mods that I did:
1x120mm fan blowing in onto the bottom of mother board on the side panel
1x 80mm fan blowing in onto the top of the motherboard (CPU) on the side panel
2x50mm fans blowing into the HDD cage in the front
1x80mm fan exhaust in the front (where the intake used to be)
1x92mm fan exhaust in the back (where there used to be a 80mm fan)
1xPCI slot exhaust fan

....these along with the 92mm fan cooling my slk-900a, and a small Vantec Iceberq fan cooling my northbridge, and the two fans in the PSU...I count 11 fans total! Well, my temps have gone down a good 5-6 degrees C, but made my computer ALOT louder. I think the 92mm fan in the back is the loudest, so I may replace that.

....are all these fans OK with my PSU?....or have I put too many fans that will put a major stress on it? Also...does anyone know if this is a good airflow in/out ratio?

Checking the voltages on MotherBoardMonitor, the +5, and -12 voltages seem way out of wack. I'm getting 4.6 for +5, and -13.15 for -12. Are these calls for concern?

 

[beatle]

The -12v rail isn't used in a modern computer system. Don't pay it any attention. My -12v rail runs @ -7v. The +5v rail should be closer to +4.75v (within 5%). Fans all run off the +12v rail. I doubt your total power consumption from fans is more than 25 watts.

You likely won't notice much of a difference in temps if you change your configuration. Front fans should be intake (have the 1 80mm fan in front blow IN. Ditch the 2 50mm fans. Ditch the 120mm fan. Ditch the PCI slot exhaust. Unless you made the hole bigger for the 92mm in the rear, it's likely not blowing any more air out of the case than the 80mm was. I'd put the 80mm back in that spot.

 

[govtcheez75]

hmm...I put a thermaltake fan controller on my home made fanbus, and am running everything at "medium", and the noise has come down alot. The temps are staying right at 39 idle, and 49 load too.
....I think the 120mm fan on the side is making a huge difference. Before I put that sucker in, I was getting 43-45 idle, and 55-60 load.

....oh, and as for the 2 50mm fans...I just put them there, to cool the HDD.
I seriously doubt they do anything to cool the case, or my processor.

 

[beatle]

The 120mm fan probably moves the most air, but at the bottom of the motherboard, it's not going directly where it needs to go: the cpu and video card. Experiment and see what works out the best. Every case is different. IDE/ATA hard drives don't NEED cooling. Mine get cooled because my case's intake just happens to be in front of them. If my intake were smaller than 80mm I don't think I'd be using it.

 

[Zepper]

Generally it takes 4 to 8 fans to put a 1 Amp load on the 12V rail. The draw for each fan is on its label - most are from 0.13 to 0.25 Amp.
.bh.
:moon:

 

[govtcheez75]

Originally posted by: beatle
The 120mm fan probably moves the most air, but at the bottom of the motherboard, it's not going directly where it needs to go: the cpu and video card. Experiment and see what works out the best. Every case is different. IDE/ATA hard drives don't NEED cooling. Mine get cooled because my case's intake just happens to be in front of them. If my intake were smaller than 80mm I don't think I'd be using it.

Now that I think about it....I don't think they do anything. But oh well, they are in there, and don't make any noise, and don't draw that much power, so I will leave them in. More of a hassle taking them out now, as I glued them on with Arctic Alumina adhesive!
....as for the other fans. I put the 120mm, 92mm exhaust, and the two 50mm fans on a TT fan controller (low/medium/high) switch that comes with some of their fans, and they are now all on low, and are whisper quiet! I did notice a few degrees increase from the high or medium settings on idle, but on load, it's still not going past 49degrees, so I am happy!
...I think I finally got everything dialed in the way I like it. I don't know, but maybe the 120mm fan blowing on my 9700pro will also help me get a better overclock?!?


....also. I am, interested in putting a blowhole, but there really isn't too much room for one up there. The CD drives come almost right up to the PSU. Infact my rounded cables that swing around from my CDRW drive to the DVD drive touch the PSU! Is it ok to have a small blowhole, and no fans up there? Would that help alleviate some of the hot airflow?

 

[beatle]

Originally posted by: govtcheez75
....also. I am, interested in putting a blowhole, but there really isn't too much room for one up there. The CD drives come almost right up to the PSU. Infact my rounded cables that swing around from my CDRW drive to the DVD drive touch the PSU! Is it ok to have a small blowhole, and no fans up there? Would that help alleviate some of the hot airflow?

It definitely couldn't hurt. Hot air rises of course and it will keep air from stagnating at the top of the case. Obviously it won't be as effective as an active blowhole, but it may help a bit. Personally, I wouldn't cut a hole in the top of my case unless a fan was going in that position.

 

[ToxicWaste]

I agree with beatle (again), you probably don't want a hole with no fan. For what it is worth, a passive blow hole may blow or may suck, depending on the pressure differential created between the total amount of air being pushed in and the amount being pulled out. So, if you are pushing a higher volume of air into your case, then the blow whole will blow, if you are pulling more air out of your case then your blow hole will suck. Hope that made sense. If you fans are unobstructed and you know their cfm ratings, than you can calculate the approximate amount going in and going out. If they are obscured by your case, then there is no easy way to calculate the amount pushed in versus the amount pulled out....

Toxic