front case fan

Lt_Dan · Post by **Lt_Dan** » Wed Apr 09, 2008 11:17 am

hello everybody,
I have a Gigabyte Poseidon case, i just changed the rear fan to a 1200 s-flex.
my front fan is Gigayte made, i don't know it's speed. does anyone know?
also, the hhd cage was behind it but i suspended the drives in the upper cage (where the CDRW go) so they don't get cooled by the fan. just by the intake of my ninja.
i have a passive gpu, do you think i can cancel the front fan? i think it spins lower the 1200rpm.
i can't control my rear fan, and it will spin faster i think then the old Gigabyte one.
the 2 fans can be connected on the same power line - which splits into 2 lines. does it matter if they are on the same one - if they are different speeds? can i connect the split line to the mobo or directly (with a molex which comes with it) to the psu cord? (like it used to be).
thanks a lot,
Dan.

jhhoffma · Post by **jhhoffma** » Wed Apr 09, 2008 4:05 pm

Hello,

If I understand your questions right you want to know if you can 1) get rid of the intake fan, 2) use two fans on one power line.

1) Most definitely! If you only have the one intake in the front, your other exhaust fans will cause a negative-pressure situation where air will be sucked in through the exhaust without the need for the fan, provided that you do not have many obstructions blocking the airflow. If you did it might be best to leave the fan in and run it slower by undervolting.

2) If your fans use a 4-pin molex connector, then you can connect several of them together (daisy-chaining) at least to the point your PSU will handle (not usually a problem for fans as they are low power). However, if you use 3-pin connectors for connecting to the fan headers, then it would not be advisable for you to connect more than one to the header as they don't provide as much power and can be blown out.

However, you can always change the speed of a fan (particularly 4-pins) with a little rewiring. Use this guide to help you in your endeavor.

Lt_Dan · Post by **Lt_Dan** » Thu Apr 10, 2008 3:23 am

you summed my question really nicely! thanks.
but i didn't get your 1st answer - is disabling the front intake fan which revs slower (i think) then the rear outtake 1200 rpm one - is ok? will the rear give enough pull?
i don't really want to start messing with wires b myself because i don't want to risk it
is it ok for 2 fans rotatig on different seeds connect to the same power lead?
thanks again,
Dan.

jhhoffma · Post by **jhhoffma** » Thu Apr 10, 2008 7:31 am

Lt_Dan wrote:you summed my question really nicely! thanks.
but i didn't get your 1st answer - is disabling the front intake fan which revs slower (i think) then the rear outtake 1200 rpm one - is ok? will the rear give enough pull?
i don't really want to start messing with wires b myself because i don't want to risk it
is it ok for 2 fans rotatig on different seeds connect to the same power lead?
thanks again,
Dan.

Well, only you can know for sure the answer. Try it and see what your temps do, particularly on your HDDs. If your temps don't suffer to terribly, then you'll be fine.

You can connect two different speed fans on the same line no problem. By default fans will run at 12v. Different speed fans are just designed to run at different speeds using that same 12v. Many people hear talk of undervolting their fans, which you do by sending a lower voltage (using a fan controller or hardwiring) to a 12v to make it spin slower. This does not damage the fan and can make a fan that's loud by default, quite quiet at a lower speed.

Lt_Dan · Post by **Lt_Dan** » Thu Apr 10, 2008 8:01 am

i just noticed the cable was split onto the 5v lines (at default) and it gets split into 2 5v fans.
this is my setup:

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the cable splits into 2 later on.

jhhoffma · Post by **jhhoffma** » Thu Apr 10, 2008 11:36 am

So you say your fans are running at 5V right now? If so, and you're still having issues with noise, then you'll need to get some quieter fans. I would recommend Scythe Slipstream 800rpm. You can also go with the 1200rpm if you want to undervolt but leave some room for going back up to full speed.

Lt_Dan · Post by **Lt_Dan** » Thu Apr 10, 2008 2:09 pm

it's not really noisy. i just didn't know if it's ok to connect them like that or is the front fan important.