Running big fans from the 3 pin MB connectors - Average wattage???

[Henny]

Anyone know the average capacity of the 3 pin fan connectors on typical motherboards. Are they OK even for typical 120mm fans??

 

[GalvanizedYankee]

You must look at the spec provided by your mainboard provider.

My ASUS is 8W for the CPU HS fan header. 8W/12V=.666A and I have no need for that powerful a fan.

...Galvanized

 

[the cobbler]

don't use them. connect directly to the PSU. the motherboard has enough things going on without having to route voltage to a bunch of fans imho.

 

[Fullmetal Chocobo]

It changes per mobo / manufacturer, so as GalvanizedYankee said, you have to check. I previously contacted Supermicro about my board (X5DAE), and each fan header supports up to 1.5a.

 

[Henny]

Originally posted by: the cobbler
don't use them. connect directly to the PSU. the motherboard has enough things going on without having to route voltage to a bunch of fans imho.

For the CPU it's nice to use the 3 pin header because you can spool it down via BIOS setup to reduce noise when things are under normal load. And the current crop of high end HSF's use 120mm fans.

I'll see if it's spec'd by the MB manufacturer.

 

[TrevorRC]

Originally posted by: GalvanizedYankee
You must look at the spec provided by your mainboard provider.

My ASUS is 8W for the CPU HS fan header. 8W/12V=.666A and I have no need for that powerful a fan.

...Galvanized

The new one won't draw that much? I know the 120x38 SD's take .52A; I'd assume yours gets even closer.

And, at the OP... RTFM. [Or, a bit more politely, please read your manual... it's all in there.] Even then, you should probably hook it up directly to your PSU.

--Trevor

--Trevor

 

[GalvanizedYankee]

Are you going to be putting this 120mm@32W beauty on your HS?? 😛

http://www.sidewindercomputers.com/de12gf.html


...Galvanized

 

[Operandi]

Like others have said it varies from board to board but if you can't find hard numbers anywhere I was say no more then 6-7 watts to be on the safe side, which really should be ok for most fans including 120mm variants.

Originally posted by: GalvanizedYankee
Are you going to be putting this 120mm@32W beauty on your HS?? 😛

http://www.sidewindercomputers.com/de12gf.html


...Galvanized

I think my ears are starting to bleed just from looking at that :Q.

 

[Zepper]

Holy shiite, batman! I could stack three or four of those and have a chimney on my case... 😉

OP,
If you keep it to .5A or less on a mobo connector you should be OK.

.bh.

 

[Howard]

Some fans come with both a 4-pin Molex and a 3-pin mobo header. When both are plugged in, does the 4-pin share the draw?

 

[BlueWeasel]

Originally posted by: Howard
Some fans come with both a 4-pin Molex and a 3-pin mobo header. When both are plugged in, does the 4-pin share the draw?

I've wondered that myself.

 

[GalvanizedYankee]

Originally posted by: Howard
Some fans come with both a 4-pin Molex and a 3-pin mobo header. When both are plugged in, does the 4-pin share the draw?

Think. The crazy fan I linked only has the tach feed wire in the three pin shell.

If one were to power a fan from the board header as well as the 4 pin Molex, there would be a conflict of interests here 😉 The board would want to regulate the fan and the 4 pin Molex would say no, your getting 12V no matter what. I think it would be bad for the board.


...Galvanized

 

[Zepper]

When they come like that, often (I've seen it this way on Vantec) the power comes by the 4-pin (red and black) and the speed sensor wire and ground (yellow and black) are the ones on the 3-pin. I suppose some have a power Y on them (red and black to both). In that case, use one or the other not both.

.bh.