I'm building a new computer. The fan connectors on the mobo are 4 pin. All of the case fans (all 5 of them) are 3 pin. I need adapters for these. The fans come with Molex adapters but I'd much rather plug them directly into the mobo. I don't need extension cables. I'd rather buy from the US as I don't want to wait 2 weeks+ for something from China.

I've tried looking on Newegg but I can't tell what will work and what won't.

Monoprice? In my experience though I've been able to plug 3 wire fans onto 4 pin plugs. I think the fourth cable might be for fan speed? Been a while though and I might be remembering wrong. Haven't built a PC in about 3 years.

quote Originally posted by ls3mach: Haven't built a PC in about 3 years.

That's my problem. I haven't built a new computer in about 5 years. (And I have CRS.)

quote Originally posted by Monkeyman: That's my problem. I haven't built a new computer in about 5 years. (And I have CRS.)

Hit it with a meter. I think extensions or new fans will be your only other alternative.

I wouldn't know what to do with a volt meter. I'm not buying new fans. This case has 6 (3x 200mm (top/exhaust), 1x 230mm (front/intake), 1x 140mm (rear/exhaust) & 1x 80mm (internal/GPU). I can see spending another $100 for new fans. If I have to, I'll use the included Molex adapters (that's what I did in my current computer). I'd just rather use the mobo ports/connections.

[This message has been edited by Monkeyman (edited 03-23-2017).]

Wait are these the typically white 4 pin on the fans that are around an inch long? And you're wanting to go for the typically black ones that go to jumpers on the mobo? If so I always just hook up one and them daisy chain them like Christmas lights.

The big white ones are Molex. That's what I used on my current (old) build. (I daisy chained them, too.) All of the fans for the new build have Molex adapters. The ports/headers/connectors on the new mobo are 4 pin (NOT Molex). They look just like the little 3 pin connectors on the fans but with one more pin.

Maybe I used Molex on the old build because there isn't any such thing as a 3 pin male to 4 pin female adapter.

http://www.intel.com/conten...oards/000005560.html

Most motherboards nowadays have PWM fan speed control. The connectors that they use are basically a 3-pin header with an extra pin (for the PWM signal). These connectors are backwards compatible with 3-pin fans; you just lose the PWM function. As a matter of fact, the PWM headers on the mobo are designed to prevent you from plugging in a 3-pin fan incorrectly.

Molex connectors are basically obsolete on computers now. Disc drives don't use them anymore, because they've all moved to SATA connectors. And fans have transitioned to the 3-pin and 4-pin mini connectors. That said, you should be able to use Molex to 3-pin adapters, if you wanna keep your old fans. Your old fans probably don't have PWM capability, so there's no sense in searching for Molex to PWM adapters.

[This message has been edited by Blacktree (edited 03-23-2017).]

Thanks, guys! Since I wouldn't get fan control with a Molex adapter anyway, I'll just plug the 3 pin connectors into the 4 pin mobo headers. Much cleaner and less wires for better airflow. All 3 of you rock!

quote Originally posted by Monkeyman: .........Windows........

quote Originally posted by Monkeyman: Thanks, guys! Since I wouldn't get fan control with a Molex adapter anyway, I'll just plug the 3 pin connectors into the 4 pin mobo headers. Much cleaner and less wires for better airflow. All 3 of you rock!

this is what MoBo are wired for. new MoBo just added extra PCM pin didn't change connector otherwise.
Pins are −/ground +12v Tach and if use PCM.

Plus MoBo will control speed for most 3 pin fans.

Fans w/ temp sensor speed control built into them can fail to start or stop later w/ MoBo fan control active too because voltage gets too low.
Fans w/ this are most easy to see. The PC on the fan have a small part stick in the air stream.

Some fans just hate low volts but most time you set low speed. Exactly how depend on "BIOS" and other software used.

BUT "daisy chaining" 3 wire and 4 fans power by fan "ports" are not allowed and will cause problems because MoBo Tach pin expect 1 signal.
You can get a spliter w/ 2 or more fan ports but only 1 fan is wired to be seen by MoBo tach pin. (more then 1 fan per MoBo port could overload the port.)

quote Originally posted by Monkeyman: The big white ones are Molex. That's what I used on my current (old) build. (I daisy chained them, too.) All of the fans for the new build have Molex adapters. The ports/headers/connectors on the new mobo are 4 pin (NOT Molex). They look just like the little 3 pin connectors on the fans but with one more pin.

Nope. The Small 3 or 4 pin fan connect on most MoBo are a Molex format/type connector.
Molex makes many connectors and other parts use make PC and many other things. Including much smaller connector for laptops etc. (I'm not digging thru the catalogs to find them.)

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

quote Originally posted by williegoat:

Normally, I would agree with you however....I have a couple of programs that won't run on Linux and my new mobo is UEFI. I was using Linux LIte (and still have that on my laptop) but it doesn't support UEFI only BIOS. It is what it is.

[This message has been edited by Monkeyman (edited 03-24-2017).]

Ogre made a good point: Modern motherboards with PWM fan control can usually throttle non-PWM fans also. But the non-PWM fan control isn't quite as good. I think it regulates voltage on the non-PWM fans. If the voltage gets too low, the fan will stop working. The minimum required voltage depends on the fan. But with PWM, you can slow down the fan until it's barely moving, and it will keep working.

Another cool thing you can do (pun intended ) is temperature-based fan speed control. So when you're surfing the internet and checking your email, the fans are silent. But when the computer starts working hard, the fan speed ramps up to keep the heat under control.

quote Originally posted by Monkeyman: Normally, I would agree with you however....I have a couple of programs that won't run on Linux and my new mobo is UEFI. I was using Linux LIte (and still have that on my laptop) but it doesn't support UEFI only BIOS. It is what it is.

https://www.linuxliteos.com...-uefi-fully-enabled/

beside that... Setting in UEFI can effect any older OS and stop them to boot.
First thing is try...
Disable Secure Boot.
Set HD ports to legacy/IDE

But HD port settings do not affect HD but IDE can disable trim and other functions w/ SSD

Examples:
WinXP need both unless you have raid/ACHI drivers and floppy drive to load them w/ a fresh install.
Win7 got an update a while back and now won't boot w/ SB active w/ many MoBos.
Many Linux version need both or only SB disabled

I have not personally tried it, but Debian should have no problem installing and booting with UEFI. It's all handled by GRUB, so theoretically any distro could be made to work.
What I do is run a Windoze VM for the few Win only apps that I use.

https://wiki.debian.org/UEFI

[This message has been edited by williegoat (edited 03-24-2017).]

quote Originally posted by Blacktree: Ogre made a good point: Modern motherboards with PWM fan control can usually throttle non-PWM fans also. But the non-PWM fan control isn't quite as good. I think it regulates voltage on the non-PWM fans. If the voltage gets too low, the fan will stop working. The minimum required voltage depends on the fan. But with PWM, you can slow down the fan until it's barely moving, and it will keep working. Another cool thing you can do (pun intended ) is temperature-based fan speed control. So when you're surfing the internet and checking your email, the fans are silent. But when the computer starts working hard, the fan speed ramps up to keep the heat under control.

Yup.

PWM does give more control vs. volt regulated power to a fan.
Note that most 4 wire fans to work w/ 3 pin ports on older MoBo. Fan see no PWM line then default to work as 3 pin fans.

Most MoBo made in last 10+ years can manage fans speed but many never set this up in the BIOS/UEFI or in the Software/OS.
The default "BIOS" for quiet operation is "standard" that gets enough power to try to make sure all fans to run reliable.
In Silence mode w/ default settings:
"BIOS" monitor may trip a warning a fan is stop or to slow. Very common w/ 120-140mm fan that spins fine @ 400-600RPM but default warning @ 600RPM or more.
volt regulated speeds can make fan to shut down, may hurt/kill in the long run because have power but not enough to do anything.

Fan speed programs and tools to monitor them often won't report all fans you have. (Newer UEFI GUI "Basic" page often don't have all data either.)
PC wizard, speedfan, and others go thru the OS to see and OS and chipset may not report them.
If dealing w/ Dell HP and others then may not report most or all fan speed and MoBo temps. Most tools only get CPU and HD temp and a few other metrics depending on Brand and Model.

[This message has been edited by theogre (edited 03-24-2017).]