Thanks. I'd found the ASUS BIOS Tool after posting and come to the same conclusion -- no invisible menu items present in the metadata. Any idea whether AHCI support is actually in there, just waiting for the right bit (or two) to be flipped in the NVRAM? I guess seeing whether there's an extension BIOS for the ICH SATA controller would be a big hint? I understand how people manually find and enable VT support in NVRAM -- by looking for rdmsr -- but I have no idea what steps are necessary to switch the ICH chip into AHCI mode so I haven't a clue what I'd be looking for in the BIOS code.
I'm asking because I just installed an Intel SSD that relies on native command queuing to reduce write amplification... in legacy IDE mode, no NCQ
Of course since the boot sequence seems only to support IDE-mode drives, that might get broken by putting the SATA controller into AHCI.
All kinds of questions with no answers. Does the SATA controller enumerate differently on the PCI bus to cause Windows to match it with AHCI drivers? Currently it is 8086:27C4 and I have a separate 197B:2360 supporting the eSATA port in AHCI mode for hot-plug detection (which I believe is not bootable) and my PCI-Express card appears as 197B:2363 -- interesting, same vendor as the onboard second controller. Anyway since the PCI-Express card won't appear in the boot order, I just I should assume that ICH in AHCI mode wouldn't either, and therefore I should consider this as a lost cause short of Intel providing a miracle BIOS update. Oh well.
Thanks again for checking it out for me.