The quest for finding out what the heck is ASUS doing with renaming IR chips:
The old ASP1251 that was reported by a few sources to be really an IR3563A, next to a IR3563A:
The ASP1252 that I suspected it's an IR3563B:
Error. It's 10 vs 12 pins. It's not the same.
What about the ASP1257?
An IR3580 perhaps?
Or an IR3563B?
What are the alternatives?
An ISL6388 perhaps that MSI got?
Aha, 10 pins.
That might might mean the 1252 is actually an ISL. With the 1257 maybe being an IR 3563B or 3580
What does the ISL6379 used on Asrocks look like?
Bummer. It's 12 pin. ASP1257 chip can be that.
Alternatives to IR for digital controllers don't appear easily. The CHL8328 from older boards is 14 pin so it's out of the question.
But we derived:IR Controllers are 12 pin so ASP1252 is not an IR.
What ASP1252 or ASP1257 actually are is probably inconclusive with the information at hand.
note: The ISL controllers tend to be on 6 or 6x2 phase cards so they might be restricted to that. Hard to google their specs. I may continue tomorrow.