First Build - Dumb Cooling/Fan Question! ^.^

[guptasa1]

Hey all,

First build, and I think I overdid it a bit on the fan front (don't plan to overclock but do like a nice, cool, stable system). Working with an ASUS P5E3 Premium Wi-Fi btw in a Silverstone Temjin TJ-09 case with a PC Power & Cooling Silencer 750 PSU. Anyway...

Here's the deal. I'm going to have 5 chassis fans, the two that come with the case, and I went with the optional three the case has places for (all of these are 3-pin plus molex EXCEPT one, which is just 3-pin for everything). An Arctic Cooling Freezer 7 Pro will be the CPU fan. And then there are also two little 3-pin only fans that come with the motherboard that I don't think I need to install (it actually says not to for active cooling). I also got the optional 3-pin Corsair Airflow RAM cooling fans which I would like to install.

My motherboard has 1 CPU fan connector (so that's fine), then 4 chassis (BIOS controlled I assume) connectors as well as a fan power connector (I assume non-BIOS controlled).

This will leave me one 3-pin plug short (or 3 if I wanted to use the optional fans).

Suggestions?

I *believe* for most of the case fans you can hook up just the molex power connectors and not the 3-pin fan controller connector, but I'm not positive what result that would have (and there aren't any instructions with the fans)...

Also, I might consider installing those two small optional fans if I thought I could fit them, but I don't know that would really help things, and there's definitely no room to plug them in.

Any advice would be great - thanks!

Moved to the Cases & Cooling forum, you'll get your answer there.
MarcVenice -- General Hardware Mod

 

[BTRY B 529th FA BN]

They have 3 pin splitters at micro center

 

[guptasa1]

Nice! That might be a good option - thanks! Though if I can get away with not using a splitter, even better. Anybody know what will happen if I don't hook up the 3-pin on one of the 120 mm fans and just hook up power?

 

[herm0016]

you are only doing one or the other right? molex or 3pin? if you do both you could smoke the board, the fan, the power supply or all 3. the 3 pin will supply power to the fan and rpm to the mb, the molex will supply power to the fan only. if you want to power them from molex and monitor the rpm cut the red and black wires on the 3 pin and just have the yellow one going to the mb for the rpm input.

 

[guptasa1]

These fans only have red and black for molex and yellow for 3-pin, so (if I understand right), you have to use both. I see what you mean if both connectors had all three wires, but that is *not* the case. Good info nonetheless though.

 

[guptasa1]

I guess what I'm wanting to do is find a way to hook them all up without having to resort to a fan controller. A splitter would work, but if I can just hook up the fan without the yellow wire (RPM monitor) and have it run at max speed, I'd also be happy with that. Will that work?

 

[herm0016]

you do not have to have the yellow wire hooked up.

 

[guptasa1]

Great - then in that case as long as it'll run full speed without the yellow wire (I take it that is what you are saying), I can hook up something else that requires the 3-pin and just use molex to power one of the 120 mm fans (probably the hard drive cage one)! Thanks! (Any other feedback/suggestions of course appreciated!)

 

[DSF]

With any fan, there are four potential wires. Ground, power, speed reading, and speed control. The molex connectors just supply power to the fans, because the two connectors they leave you are power and ground. The yellow wire that's in the 3-pin motherboard connectors is the speed reading wire. It sends data from the fan to your motherboard (which can then be reported by certain programs) about how fast the fan is spinning. It's not terribly important, since you're not going to be changing the speed on those fans. The fourth wire, which only shows up on the CPU fan in most systems, is the wire that allows the motherboard to change the fan's speed. (Slowing it down when it's not needed, speeding it up when things get hot.)

So to recap, plug as many fans as will fit into the motherboard, if you want to. (Note that PWR_FAN, if you have that connection on your motherboard, is not for regular fans.) The rest can run on molex and be just fine. Some people even cut off the unused molex or motherboard connectors from their fans to get rid of the clutter if they know they aren't going to use those connections.

 

[guptasa1]

Ohhh...so essentially that yellow wire just says "Hey - I'm running normally." The computer won't even be controlling the fan to begin with - just "seeing" it. So it'll run the same no matter what. Good to know - thanks so much for the clarification!

However, could you please elaborate on the PWR_FAN connector? I was under the impression it was fine to hook that up to any fan from the following from the manual:

"Plug the optional fan cables to the CHA-FAN1, CHA_FAN2 or PWR_FAN connector on the motherboard."

This was in context of the optional fans that come with the motherboard (which I may not use since I'm using an active cooler), so I just assumed it would work with any fan and just not allow control of the fans (obviously wrong since there's no 4th wire on ANY of the mobo fan connectors except for CPU). Can you please enlighten me?

Thanks again for the great information! You know, they really could put more useful information in these manuals - I've noticed a lot of my questions aren't answered by the manuals in many cases.

 

[RallyMaster]

I believe the yellow wire is a speed sensor. It just tells the computer how fast it's spinning.

 

[DSF]

Actually, thinking back on it, I may be wrong that regular fans can't be used with the PWR_FAN header. The original purpose of that header was to provide RPM data on the fan inside the power supply, but not all power supplies come with that feature. I'm not sure whether it should be used with a regular fan or not.

 

[RallyMaster]

I'm pretty sure it's just a regular +12V output.

 

[guptasa1]

Well, the manual says you can with the fans they include, and it doesn't look like my PSU needs it, so I think it should be fine from that and a Google search (just have to remember that's what PSU will read). But at least I know what it's originally for now!

 

[DSF]

Originally posted by: guptasa1
Well, the manual says you can with the fans they include, and it doesn't look like my PSU needs it, so I think it should be fine from that and a Google search (just have to remember that's what PSU will read). But at least I know what it's originally for now!

The PSU doesn't read it unless the PSU is plugged into that header.

 

[guptasa1]

Originally posted by: DSF
The PSU doesn't read it unless the PSU is plugged into that header.

Right. I was thinking though, maybe the motherboard/BIOS will think whatever fan *is* plugged into that is the PSU. Could be mistaken about that though.