Have you by any chance installed a new video card? I know it sounds strange, but newer cards that use/have an hdmi output also channel sound trough that connection. This is that mysterious “high defenition” sound device. I suspect it is the case, because the Nvidia card I have (altough not an ASUS, but an MSI) also uses that high defenition audio output. Keep in mind that some motherboards have an on-board graphic “card” that can have an hdmi output too. Sometimes you than have to disable not only the primary sound device, but also the high-definition sound device.
I have no idea how to disable this hardware if you do not use an on-board card, because in that case it is not configurable in the motherboard BIOS. However - in my case I just choose my (focusrite) ASIO driver in stead of an high defenition (or any other) device from the pull-down menu in the device setup, and have no latency problem at all…
If you keep having problems you can try looking up the high definition device in the device manager and than just put an check in “do not use this device”. Do not remove the device, because it will be re-initialised at reboot. Just disable it, and Windows will not “see” the device any longer.