i just wanted to report some stuff on this motherboard.
DDR5 2x48GB 6800 G.Skill
Gainward 4090 Phantom GS (newest BIOS against black screen at boot)
PSU: Corsair AX1600i
There is an extra pin (i guess ground) besides one of the normal pin. One of the extra pin damaged 2 of my EPS cables, because i thought the first cable is faulty. But then i pushed that extra pin more away from the normal pin, so that it has the same distance like at the other EPS socket. I tested this time with the other end of the damaged EPS cable and it fully plugged in and no contacts from the cable was damaged. I did that 3 times to be sure not to damage my last EPS cable that i have from my old PC (can‘t use it now). I noticed this at the first time, because the cable was on one side 1-2mm away from the EPS socket.
Can Asus give me the money for 2 new EPS cable? PSU is Corsair AX1600i (i have two, so i could use the EPS cable from my other PC).
I turned my PC off and PSU to 0 to connect an ARGB cable - worked. PC took longer to boot, i turned my monitor later on - i forgot. While booting i pressed several times „DEL“ to enter UEFI to check if i can change color (no). When Windows booted, it installed drivers for iGPU (14900k) - it was default off and i like that Asus set this default off. So i checked BIOS and iGPU was set as primary and was activated. Somehow the UEFI activated iGPU. My monitor and Valve Index is only connected to the RTX 4090. The only thing i changed, and the UEFI shows changes at exit, to go „Stealth Mode“ with the LEDs at standby/suspension etc. mode.
When i activate S4 + S5 the PC starts, fans spin for a second and LEDs are normal on, black screen on monitor. Then i shutdown with the power button (5 seconds) start again and the PC starts normally. When i turn ERP off everything works normal.
Those cables on the 4090 video cards have been a problem since there were released. Many folks chose to replace those cables with other versions. You should be able to find info online regarding the situation. It is one of the reasons I have not gone to the 4090 cards.
The situation about the iGPU is a little unclear, but perhaps the system was seeing a problem with the card and switching to the other video source.
You mean the PCIe cables/connection for GPU, i mean the EPS connection for CPU - the extra power for CPU.
Maybe that with the iGPU happened, because i had the monitor off at cold start. I don‘t know.