What is a chipset fan?

[#1]

My BIOS told me my "chipset fan" wasn't working and invited me to ignore it or to switch off this kind of notification in the BIOS.
If a "chipset fan" is the thing that sits on top of the CPU, I'm not touching it!
That blank space at the bottom right used to read 6000 rpm.
Please note that the CPU temperature reading is when a 100% application (BOINC) of one CPU (of two) is running at 100%.

[#2]

The chipset fan is the one which cools the chipsets on the motherboard - some have a small fan on the heat sink and some use passive cooling.
If the only fan on your motherboard is the one on the CPU then it is passive cooled and you can disable the monitoring

[#3]

Thanks @oldjim
There is a very little fan on the motherboard (about 2cm diameter) - but since I'm not a mad gamer or anything, I shall let sleeping dogs lie.

[#4]

There are two reasons for it not working
One - something is knackered
Two - it is on temperature control and the chipset hasn't got hot enough (the reported motherboard temperature may be the one it is cooling and at 45 deg C that isn't a major problem)
However if it used to read 6000rpm a little investigation may be a good idea.
First check that the connection is secure on the motherboard and second does the fan rotate freely when flicked.

[#5]

Sorry Jim - I'll wait until next time I open the case - it's a bit of a performance to do so.

[#6]

If you are anything like me I only open it when I need to clean the fluff and dust out 

[#7]

Indeed!