Weird case fan setup help.

[FancyPants101]

I have an old pc with 6 80mm fans. 2 on the back top/middle, 2 on the front bottom, 1 on the side next the video cars/pcie slots, one at the top blowing out the top middle. It also has the psu next to this top fan blowing air out the back from a fan on the bottom of the PSU. I also have an old PCI fan below the video car blowing air up. And a few fans in hdd drives in the 5.25 bays because of extra hdds...

 

I thought originally I would reverse the fans. I did this and had the rear fans blowing in and the front fans blowing out. Thought maybe the hdd's woud get too warm as they are behind the front fans. Then I put both front and back fans inward blowing. This leaves the only outblowing fans the top and PSU. I have an old bus bay controller with full/off/half speed. Is it safe to run both the front and back inwards and leave the top and psu to blow out the air. The side fan cannot be reversed as it's permantly intalled. The same with the top fan. The back and front are quick slap in fans you can easily pull off and reverse..

 

The fans are all at half speed. I was hoping the double in from the back and front would create positive pressure to stop dust. Originally I had front at full and back at half. But the front fans created too much noise which prompted me to start reversing to get the noise in the back. Then I went with double in. Is there any harm in this? Assuming it makes any sense.

 

My cpu fan is doing a lot less work. Not sure if that is a good sign. And the temps seem to go up and down faster.

 

And the GPU may be blowing a small amount out the back.

[suedseefrucht]

1 hour ago, FancyPants101 said:

I have an old pc with 6 80mm fans. 2 on the back top/middle, 2 on the front bottom, 1 on the side next the video cars/pcie slots, one at the top blowing out the top middle. It also has the psu next to this top fan blowing air out the back from a fan on the bottom of the PSU. I also have an old PCI fan below the video car blowing air up. And a few fans in hdd drives in the 5.25 bays because of extra hdds...

So you are air cooling your CPU?

 

Hot air moves up naturally. So just use the front bottom fans as intake, the side fan and the fan below your graphics card can also take in air for the graphics card.

The rear fans are good as outtake, because the hot air will be at the top and they blow it out from there. And the 7th top fan should be an exhaust for the same reason.

 

[FancyPants101]

I changed the back fans to make them also be intake. It seems to help get the cpu fan to lower rpm and the cpu temps seem to respond more actively. Wasn't sure if this was bad. I have the top fan pulling out still and the psu is pulling air out with a much bigger fan naturally. And the gpu does a little. I was hoping this was a safe method. And that is might create more positive air pressure to avoid dust.

 

Yes, it is all air cooling. It's an old 1100t phenom system. Stock cooler.