I'm using the Asus X99-DELUXE-II motherboard:
2 Answers
It stands for High Amperage Fan. There should be a header (pins) on the board for you to plug in multiple fans or fans that are higher current. H-Amp fans usually have better cooling.
The manual setting for that board would allow you to set measure points and min/max temperatures, etc.
Search "High AMP" at this Asus page:
1It is High AMPerage header connection for a fan on Asus motherboards, which can provide up to 3 A for powerful fans.
