Solved Case Fans...

[DiamondNRG]

Hello,

I am replacing my case fans in my system tonight (2 of them sounded like garbage and the other 2 are just as old)

My case is setup with 2 front fans at the bottom behind a filter. I am using these to bring air INTO the case.

I then have 2 fans on the back of the case up slightly higher, I am using these to blow the hot air OUT of the case.

My question is what to do with the fan on the side of my case... IN or OUT? It does line up with the back half of my video card, but that is about all. Video card seems to stay pretty cool without it (I had been running without a fan in this spot)

My thoughts are that because its lower in the case I should bring air IN to blow on the video card. But I dont know if 3 IN and 2 OUT is bad.

My motherboard obviously has a huge CPU fan and a chipset fan and the power supply has a large downward fan.

Any advice?

Next I need to replace the stupid chipset fan as I can hear it the most now.

 

[Mark]

I have a large fan on the side of my case and it blows in, but that also has the effect of covering everything with dust. my front fans have a dust filter so they are good but I would much rather have the side fan blowing out, which would draw hot air away from the Graphics card and would result in far less dust and I have also heard that the side fans create turbulence which effects the flow of air through the system and can result in having higher temperatures.

 

[johngalt]

Usually the rule of thumb is to have more blowing in than blowing out, but just by a slight bit, IIRC.

 

[DiamondNRG]

Yeah, I thought about the dust thing, but the good news is that the case sits up on the desk not down by the floor so dust shouldn't be too bad... I could add a 3rd one for input on the front but it would be behind the door so im not sure it would help much and it wouldn't be filtered.

More in than out makes sense though...

The turbulence is the part I was concerned with...

Hmm... well I guess I will leave it like it is now with it blowing in and keep an eye on the dust. Sure wish I knew the answer to the turbulence though. Maybe some more opinions will help

 

[johngalt]

When you do the math, keeping it within 3 CFM of a difference (or, as I recall seeing at one place, no more than a 5% differential on total CFM) you should be good to go. That should not make for too great a turbulence issue at all.

With my rig, I never bothered to calculate incoming versus outgoing CFM, but since it sits close to the floor it gets dusty - quickly.

Just a couple of weeks ago I took out both 260s and thoroughly air cleaned both cards (by expending a very large can of air split between the two) and my temps dropped nearly 3 degrees both idle and under load.

I usually clean my machine out every 3-4 months b/c of the dust bunny accumulation

 

[damoh]

What i allways do is place my fans in my case, then get a match, cigarette or something that gives off smoke and hold it to the front. If they front fans are sucking in, then you should see the smoke make its way through the case. When i did it i noticed the smoke circulated around the gfx card, so i made the side fan blow out. And all is well. Simple yet effective lol

 

[DiamondNRG]

What i allways do is place my fans in my case, then get a match, cigarette or something that gives off smoke and hold it to the front. If they front fans are sucking in, then you should see the smoke make its way through the case. When i did it i noticed the smoke circulated around the gfx card, so i made the side fan blow out. And all is well. Simple yet effective lol

Excellent idea!

 

[Chappy]

Having a positive pressure situation inside the case is not good as it can create dead air spaces, it's usually best to have a slight negative pressure and then the intake fans will work more efficiently. If you have any non-fanned intakes on the case DRG, then I'd put it blowing out and allow the vent to draw in to equalize the case pressure.