Asus Pro WS WRX80E-SAGE SE WIFI II startup problems (Q-code 78)

Hardware Motherboards
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I just put together a machine with a ASUS Pro WS WRX80E-SAGE WIFI II motherboard, a Threadripper Pro 5955WX CPU and an NVIDIA A6000 GPU, but I’m getting a “Fatal Error” with the Q-code of 78 (“ACPI module initialization”) and I can’t get into the BIOS settings menu (I’ve tried two different keyboards but it doesn’t respond to pressing Del or F2 during startup). I don’t have an OS installed yet.

When I started it for the first time, it said “New CPU detected” and gave me a choice of changing the BIOS but I can’t remember what I chose. Now, on startup it shows me text indicating that it recognizes the CPU, the RAM, two M.2 storage drives, and also USB devices (“1 keyboard, 1 mouse, 2 hubs”). I am plugging a monitor directly into the NVIDIA A6000 and that seems to work, too.

I tried updating the BIOS with the “flash” button, which reads a file from a USB file, and that worked – the text on the monitor now shows the updated version.

So I seem to be pretty close to having a working machine, except for the fatal error and the fact that I can’t get into the BIOS settings.

Is the key to clear the CMOS?
An ASUS tech suggested that I clear the CMOS, and this motherboard has a “Clear CMOS” button on the I/O panel, but I’m not sure if it should be done with the machine on or off (I tried both but it didn’t seem to do anything). The battery isn’t shown in the manual, but a forum suggested that it was under the VRM cover.

Anyway I’ve run out of ideas and I’d be really grateful for any suggestions. Thanks.

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Hi,

The Clear CMOS button can be used when the system is off. You can try it with or without the power cord connected.

If this fails, I suggest reinstalling the CPU. Simply remove the CPU a few seconds from the socket and then reinstall it. Afterward, you should be able to see the prompt “New CPU detected” again when powered on.

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Thank you, that’s useful. I eventually figured out what was wrong, and it was my mistake. I had failed to provide power to the 8-pin PCIE power connector on the board (the one just below the 24-pin motherboard power connector). That’s because I figured it wasn’t needed; I was already using two VGA power cables to power the GPU, and it was working. But it turns out that providing PCIE power on the motherboard is required for it to boot correctly. I had ignored a warning “Ensure to connect PCIE 8-pin power connector to ensure system stability under heavy loading” because it sounded optional to me…but it’s not. Once the power was connected, everything worked correctly and after a number of attempts I got Ubuntu installed, so all is well.

Also for others with this kind of problem – the ASUS tech was more ignorant than I was about the motherboard, did no troubleshooting, and advised me to return it. Really not helpful.

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Thanks for this. Was worried that I had messed something up.