Knowledge

[1770] CPU fan speed control Intel motherboard using non-Intel chassis

Release date: 30 march 2010

Using these instructions is not supported by Intel and on your own responsibility.

Problem:

After updating Intel firmware (BIOS) of an Intel server motherboard fans spin extreme loud when using a non-intel chassis, like Chebro.

When updating all firmwares at some point the software want's to know what chassis the motherboard is build into. It first tries tries to find out itself, but when using a non-intel chassis it won't succeed and will ask you to select. Because your chassis is not on the list presented you choose 'Other' as chassis model. After that, the fan's spin like crazy.

Solution:

The problem (and solution) lies within the downloaded firmware. Somewhere the motherboard must have had instructions to spin the fans that fast!

This instructionset can be found in the follwing file: HC_BMC.sdr Directory Locations can be different, but in my case (S5500VCH)is was in the root of the firmware file. This is a simple text-file, so notepad will be able to open it. If done you will find all the preselected Intel models and there specific fan parameters. Because you use a non-intel chassis we are intrested what can be set when choosing the 'Other' model. It's a huge file but it's build pretty organized. In my case, this is what I found:

// Fan Sensor Scaling SDR Record //====================================================================// _SDR_TYPE C0 _SDR_TAG 'OTHER' _SDR_TAG 'FCT' _SDR_TAG 'FOQM' _REC_LEN 001B // Sensor Record Header 0085 // Record ID 51 // SDR Version C0 // Record Type 16 // Record Length // Record Body Bytes 570100 // Manufacturer ID 0A // Record Subtype Value******* Fan Sensor Scaling SDR Record ********** // Fan Sensor Scaling Record 00 // Return Format; Bit 0=Fan 0, Bit 1=Fan 1; etc. 0=RPM, 1=Period(***TBD***) 00 // Number of tach Pulses Per Revolution: Bit 0=Fan 0, Bit 1=Fan 1, etc.; 0=2 Pulses/Rev, 1=1 Pulse/Rev(***TBD***) 401F // Placeholder for Processor 1 Fan(SN:0x30), Max RPM: 8000RPM == 0x401F (the order is LSB, MSB) 401F // Placeholder for Processor 2 Fan(SN:0x31), Max RPM: 8000RPM == 0x401F (the order is LSB, MSB) 0001 // NULL(SN:0x32) B414 // Placeholder for System Fan5(SN:0x33), Max RPM: 5300RPM == 0xB414 (the order is LSB, MSB) B414 // Placeholder for System Fan4(SN:0x34), Max RPM: 5300RPM == 0xB414 (the order is LSB, MSB) B414 // Placeholder for System Fan3(SN:0x35), Max RPM: 5300RPM == 0xB414 (the order is LSB, MSB) 7017 // Placeholder for System Fan2(SN:0x36), Max RPM: 6000RPM == 0x7017 (the order is LSB, MSB) 7017 // Placeholder for System Fan1(SN:0x37), Max RPM: 6000RPM == 0x7017 (the order is LSB, MSB)