Maximus Z890 Apex does not recognize old Radeon HD4890 card (Q-Code D6) used for debug.

[OldGuy17]

Sorry for the long post, but I want to ensure that you have all the info you might need in order to help me with this issue.

Looks like the BIOS shipped with my new ROG Maximus Z890 Apex does not recognize an old (15 yrs) Diamond Radeon HD4890 graphics card (with dual DVI monitor interfaces, and whatever version of PCIE was common back in 2009): After pushing the Start button on the MB, I get a long (about 1-2 minutes) succession of Q-Codes ending in a D6, with a painfully bright white LED shining just above the 2-digit 7-segment displays near the Start button on the MB.

System specs as currently configured:

MB: ROG Maximus Z890 Apex

CPU: Intel Ultra 9, 285K. Heatsink: BeQuiet! Pure Rock Pro 3. Both CPU fans, and all chassis fans are running properly.

Main Nonvolatile Storage: Samsung 900 2-TB SSD (with integrated heatsink; not using heatsink that came with MB) in the main M.2 slot

RAM: G.SKILL Ripjaws DDR5, 64 GB (2x32GB), in the only 2 RAM sockets on the MB.

Power Supply (PS): BeQuiet! Straight Power 12-1000. Fan runs properly.

Graphics Card (for temporary configuration and debug purposes only): Diamond Radeon HD4890. Fan runs properly, and the two 6-pin connectors on the "VGA1" power circuits from the PS are plugged into the corresponding two 6-pin connectors on the Radeon card. (I also have an Alienware desktop, circa 2012, with 2 GeForce 760 Ti cards. Might I have better luck avoiding the D6 error by replacing the Radeon card with one of those? They also pre-date DisplayPort, and have DVI connections to the monitor.)

Monitor: Samsung B245. Connected to Radeon card via DVI cable. (Monitor stills works well, but DVI and the old 15-pin VGA are the only ways to connect to it.)

I am using the Radeon card (and my old monitor) just to debug the motherboard installation before installing an ASUS GeForce RTX 5070Ti, and connecting that graphics card to a new ASUS monitor via DisplayPort.(Based on my experiences with computers over the past 40+ years, things generally end up working best when I don't try to use all-new components all at once).

My question is this: Is there any hope that I can get this MB to recognize and work well enough with the Radeon card to configure the BIOS, test the RAM and SSD, install Win 11 Pro, and address any lingering Q-Codes indicating other problems, before I integrate the new graphics card and monitor into the build? If so, please suggest actions I might take to make that happen. If you are certain that I cannot make this work without heroic measures, is there a known issue with my MB that prevents it from finding old graphics cards? In that case, I guess I'll have to install the 5070Ti and the new monitor, to see if those replacements will avoid the D6 failure while also not introducing more errors.

Thank you for any help you can provide!

[OldGuy17]

So, I just turned off the PS switch, made sure the monitor was off, removed the 5070Ti (so there is now no external graphics card on the MB).

I connected a unidirectional Thunderbolt4-USB-C to DisplayPort 2.1 cable into the rear-panel C1 connector, and into DP1 on the monitor (which is set to automatically find which port has a signal). I turned on the monitor, switched on the PS, and used the start button on the MB to start the boo process. Same result as always: boot process terminated at D6, with the monitor never receiving any signal from the iGPU. I used the start button to shut down the stalled computer, cleared the CMOS again, and moved the USBC side of the graphics cable from rear-panel Thunderbolt 4 connector C1 to C2. I used the MB start button to restart the boot process. As usually happens after I clear the CMOS, the MB cycled through some Q-Codes before shutting itself down and restarting. More !-Code cycling, ending once again in D6 (with the usual white and red LEDs above the 7-segment LEDs lit).

How can I force the MB to use the iGPU without being able to get to the BIOS? This situation looks like there is a hardware problem with the MB.

I disconnected the USBC-DP cable from the rear-panel C1 connector

[Nate152]

At default settings the motherboard should automatically detect what graphics output you're connected to.

The ROG Maximus Z890 Apex has the bios flashback feature, all you need is a usb flash drive and power to the motherboard to reflash/update the bios.

Updating the bios could possibly fix the D6 error, If you'd like help updating the bios, just say so and I'll list steps how to do it.