I would strongly advise against running more than 2 low power fans on a single motherboard header, you will very likely end up damaging it.
Weird thing is I checked the motherboard manual last night hunting for the fan controller specs and after bad mouthing them yesterday I found the precise information and it's good news.
Apparently each header can take 24W and between the lot they can do something like 80+W! That's a whole lot more than I was expecting.
If you want to do it the right way you need something like this
. It uses the pwm signal from the motherboard to control 3 fans but sources power directly from the power supply.
Yeah I would use something like that but the door on the case necessitates a flat 5 1/4" bay and I'd hate to recess the controller. It'd just look half arsed.
You might also want to take a look at this
. It`s a cheaper alternative to the T balancer that still offers fairly decent temp based control.
That's what I've got on my 3 PWM fan setup. I just can't use it as a whole solution without finding a supplier of 140mm PWM fans and thus far the only way I've heard of is by contacting Scythe support as I think one of their HSF uses one. Aside from that it looks like an unsupported fan configuration which is a shame as I can see people using more 140mm fans in the future.
Some fans, like those cooling the hard drive might not need a fan controller at all, a simple 5 volt tweak could do. If you streamline your setup a bit, a good pwm splitter along with some more basic speed reduction methods might be all you`ll need. And if you swap the fan on the gpu you could still use the existing header to power the replacement.
A dedicated fan controller does have the advantage of letting you monitor additional temps but imo it`s not the most elegant way.
Basically, you need the two hottest components (cpu & gpu) controlling the majority of fans. A 3 way splitter on the motherboard would control the cpu fan plus one intake and one exhaust. If your video card has a pwm header you could do the same there. The hard drives could be cooled by a fan set at a fixed speed. Seven fans in total which is still overkill as even 5 should be plenty (cpu, gpu and 3 case fans).
I'm coming around to that kind of solution.
After messing around with speedfan last night it looks like with this motherboard I can only monitor fan speeds from inside windows but it does allow me to set thermally responsive settings in the bios.
I was thinking of getting another PWM splitter and daisy chaining it so I've got the two front intakes, one on the heatsink and the rear exhaust all off the CPU header. The hard drives shouldn't really overheat at all regardless but it shouldn't hurt.
Then all I'd need to do is get some fan splitters so I can run the remaining 4 140mm fans in pairs. The two intakes running off the graphics card temperature and the two roof exhausts perhaps just on like a permanent 50% setting. That should all work nicely.
As for overkill... has the Missus been on hear briefing people or something?