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ML350G6 - Reduced acoustics not available with 4th fan

 
pant9
Occasional Contributor

ML350G6 - Reduced acoustics not available with 4th fan

Hi.

 

ML350 G6, 1 proc, latest FW's.

 

Added a 4th fans, because "I can", maybe reduce the total noise, but keep the total airflow.

 

In the bios the Reduced Acoustic option will not be saved with the 4th fan connected. It defaults back to Optimal Cooling next time I check the bios.

 

With 3 fans the RPM's are 13%, 13%, 17%, but increase to 15%, 19%, 21%, 21% with the 4th fan. 

 

I don't understand why adding a 4th fan should increase the fan speed.  To keep the same airflow all fans could reduce the speed.

 

Can someone please enlighten me?

1 REPLY 1
stuko
Advisor

Re: ML350G6 - Reduced acoustics not available with 4th fan

You know what, its actually even worse than that...

 

On mine with the latests BIOS etc, not only do you need to remove the 4th fan, you also need to install a random PCIe card into the top slot, in order for the reduced acoustics to kick in.  

 

So you have to make the server consume more power, and have 25% less cooling ability, in order to enable the low noise low cooling mode.  Unbeleivable.