Current limitation of motherboard fan headers

[PurdueRy]

Back in "the day" I use to read how you shouldn't hook 120mm fans to the mobo's fan headers due to them not being designed for the current these fans pull(since the 120mm fan craze wasn't quite in full swing yet).

Does anyone still not connect these to the mobo? Are they still designed for only the current a 80mm fan pulls?

 

[Tweakin]

I'm trying to find out the same thing. A long time ago it was limited to .1amp I believe, which at the time rulled out all the 120 fans. I'm hoping this has gone up as it would give most of us some additional viable options for silent operation.

I sent off an email to Abit requesting information on the IP35-E, but I really don't think I will hear anything back.

 

[DarkRogue]

I currently have 3 120mm fans hooked up to my motherboard's fan headers with no ill effects. I'll eventually swap them over and hook them directly to the PSU so I can hardwire them to 5v but yeah, I don't have any problems with it.

 

[imported_Scoop]

Originally posted by: Tweakin
I'm trying to find out the same thing. A long time ago it was limited to .1amp I believe, which at the time rulled out all the 120 fans. I'm hoping this has gone up as it would give most of us some additional viable options for silent operation.

I sent off an email to Abit requesting information on the IP35-E, but I really don't think I will hear anything back.

I have my rear exhaust fan, 0.16A, connected to the IP35-E's sysfan header. In general I don't think there's a problem as long as you don't split the headers and connect more than one fan to each.

 

[Tweakin]

Originally posted by: Scoop

Originally posted by: Tweakin
I'm trying to find out the same thing. A long time ago it was limited to .1amp I believe, which at the time rulled out all the 120 fans. I'm hoping this has gone up as it would give most of us some additional viable options for silent operation.

I sent off an email to Abit requesting information on the IP35-E, but I really don't think I will hear anything back.

I have my rear exhaust fan, 0.16A, connected to the IP35-E's sysfan header. In general I don't think there's a problem as long as you don't split the headers and connect more than one fan to each.

Thanks, that makes sense. The old limitation needed to be addressed several years ago, and with some of the newer MB's allowing for speed sensing on the headers, it makes for a nice quiet system.

 

[Miramonti]

With an ip35 pro I connected 2x120mm's to one fan header for a while (actually 2x120mm's twice, for a total of 4x120 at the same time), altho decided I wanted to use a fan controller for manual control instead.

 

[Modelworks]

The fan headers on the gigabyte p35-ds3l board I have here are fed by fets that can source 10A of current easily, but not with the trace widths they have feeding it.
So atleast on this board its a trace limiting the current and not the parts connected to it.
How much the trace limits it I have no idea, but the stock intel fans draw 450-550 ma or .5A.

 

[Miramonti]

Originally posted by: Modelworks
The fan headers on the gigabyte p35-ds3l board I have here are fed by fets that can source 10A of current easily, but not with the trace widths they have feeding it.
So atleast on this board its a trace limiting the current and not the parts connected to it.
How much the trace limits it I have no idea, but the stock intel fans draw 450-550 ma or .5A.

And yate loon 120's draw .3 amps at full load.

 

[Ratman6161]

This was a problem back in my Athlon XP days, but on recent motherboards it isnt an issue. They are designed to handle it. And if you don't connect the fan to the motherboard's header, you loose the ability to monitor fan speed.

Finally, I've got three 120 MM fans connected to the motherboard at the moment. But they are all turning at just over 1000 RPM. I can't quote you numbers but I cant believe that the 120's running that slow draw as much power as the old 80MM fans that ran at much higher RPM to achieve the same air flow.