CPU header Voltage on Dell Micro

I have a;

7070 Micro 9700t,

7070 Micro 10500t and

7010 Micro 13500t.

I am wondering if I can change the 5V cpu fans to 12V units for better cooling.

Do the Dell Micro boards support 5V only or are they able to support 12V fans also?

Has anyone tested the pins? Or how do I test them?

Regards.