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Done a bit of Case Fan research and I have a few questions

Last response: in Systems
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September 2, 2011 7:15:21 PM

I wanted to ask some things about case fans, it's my first time building a custom desktop and I figured this is the best website to ask.

1. Does the ASRock M3A UCC have enough power connectors for the 5 fans in the table below?
2. I'm using the Antec Three Hundred case, will dust guards on my intake fans be enough to protect against dust build up?
3. Can anything bad happen from negative pressure inside my case?
4. Since the Antec Three Hundred comes with a fan controller, can I control all of my fans with it, or just Antec branded ones?
5. If I can control them all, am I right in assuming that all fans have the same speed as read on the fan controller?
6. From my number crunching below, I can tell I really need the best case scenario, what is the best way to adjust my intake fans to a slower speed than my exhaust fans?

To put that last question another way, I'd like to know if I can control each fan individually. I wouldn't mind if the front two fans are controlled as a pair however.




I also forgot to add default values for CFM, in addition to the best and worst case scenario. The combination of lowest intake and lowest exhaust makes for -14.1 CFM (quietest). Highest intake and highest exhaust makes for -38.9 CFM (loudest).

Fan 1
Fan 2
Fan 3
Fan 4

Sorry for the wall of text, but I really want to get this right first time. This thread may even benefit future first time builders :wahoo: 

Thanks for reading!
a b B Homebuilt system
September 2, 2011 8:38:46 PM

1. Don't know see the mobo specs/layout online

2. Dust guards reduce the amount of dust but can't eliminate all of it. You will still need to periodically clean your fans and heatsinks.

3. Typically case fans can not produce a negative pressure in a case as they don't have the ability to create true suction. And if they could then you're inlet is too restrictive which would be very bad.

4. Fans designs vary. Some control speed by PWM and others by voltage only. Depending on the fan and readout the readout may or may not be accurate.

5. You don't necessarily want your intake fans to be running slower than your exhaust fans. What you want is good airflow thru the case around the heat generators with proper exhaust of the heated air.

Whatever approach achieves this is fine. The concept of negative case pressure is a myth. Air FLOW is what cools, not a vacuum. A vacuum is bad as there is no air to cool the components.
September 2, 2011 8:57:37 PM

So air flow of -14.1 cubic feet per minute is acceptable? I read somewhere that if there's more air pushed in than there is forced out it creates pockets of warm air that don't come out and just make the inside warmer and warmer.

The motherboard has these features(fitted with a 750W PSU):
- CPU Temperature Sensing
- Chassis Temperature Sensing
- CPU/Chassis/Power Fan Tachometer
- CPU Quiet Fan
- Voltage Monitoring: +12V, +5V, +3.3V, Vcore

- 4 x SATAII 3.0 Gb/s connectors, support RAID (RAID 0, RAID 1 and RAID 10), NCQ, AHCI and "Hot Plug" functions
- 1 x ATA133 IDE connector (supports 2 x IDE devices)
- 1 x Floppy connector
- 1 x IR header
- CPU/Chassis/Power FAN connector
- 24 pin ATX power connector
- 4 pin 12V power connector
- CD in header
- Front panel audio connector
- 2 x USB 2.0 headers (support 4 USB 2.0 ports)
Related resources
September 2, 2011 9:45:10 PM

I did some Googling on my PSU and I think it would be relevant to state that it has seven 4-Pin Molex Peripheral Connectors, so *I think* this means I can connect my five fans to the PSU with those connectors?

I've also just found out that my monitor didn't have a DVI connection and my graphics card only had a DVI and a HDMI plug, not VGA. I'm always finding something wrong or incompatible with my system :/ 
a c 136 B Homebuilt system
September 2, 2011 10:01:15 PM

You could connect about 20 fans to a single molex

blow in from the front and bottom , and out at the top and back
September 2, 2011 10:16:25 PM

Yeah, I will definitely be cleaning *this* desktop. My last desktop (I've been without one for three years) died from overheating. It lasted six years and I took it apart for the first time since buying it and you won't believe the amount of dust I found. Needless to say, I have learnt my lesson... hard.

So do those fans in my original post look good? I'm not fussed about the front two fans, as long as they are the same brand as the case and that they have LEDs, the other three I want to be a good brand however.
!