Limits on fan power from C2750D4I?

[Constantin]

I am considering migrating my motherboard from a Mini XL to a RPC-431. The latter offers 120mm fans where the Mini XL used 60mm (?) ones, two 80mm in the rear (vs. one for the mini XL), etc.

Given that I'd be installing a 650W Seasonic power supply in this case, do you think can I safely populate the fan jacks on the motherboard with 4-pin PWM 120mm and 80mm fans in place of the smaller 3-pin stuff that was put in for the mini XL?

Lastly, do you think I could use one of the CPU fan headers for a potential 3rd front fan?

As best as I can tell, the motherboard manual on the ASRock site gives no insight into the maximum fan power draw allowed...

 

[BigDave]

can I safely populate the fan jacks on the motherboard with 4-pin PWM 120mm and 80mm fans in place of the smaller 3-pin stuff that was put in for the mini X

Yes if there are four pin headers on that board, and a cpu fan header will be fine to use as well.

 

[Constantin]

They're all 4-pin fan headers with that weird offset tab to ensure that they are backwards compatible with 3-pin fan connectors. My concern was more around the total power draw of potentially fully-populating all the available headers with one fan each. The motherboard documentation re: allowable maximum power draw is nonexistent...

 

[BigDave]

typically you can run one fan @ 12 volts off each header and the load would not be an issue. The headers are made and designed to be populated so there's no
worries about an overload.
I have in the past, ran two 5 volt fans off a splitter and that never was a problem for me either.

 

[Ericloewe]

Fan header power limits are only a concern when you're talking about high-speed fans. Say, 4000-5000RPM for 120mm fans. Less if they're 32mm thick.

I'm not sure about the ASRock boards, but Supermicro boards can handle an 8000RPM 80x32mm fan per header.

If you're really concerned, you can get adapters that pass through the control signals to the header while powering the fan from a molex connector.

 

[Constantin]

I figure the 120mm fans should be fine... but given the lack of documentation on the part of the OEM board supplier, it's always better to ask before releasing the blue smoke!