Have you updated the VBIOS for your 4090? It may help with your issue...
Both the TUF and Strix 4090's have a VBIOS update (V2.0) that address the issue of the card having issue on low or idle loads. If you look at the Support page for your card, you'll see V2.1 which was to address the "ECC State" setting not being applied when setting it via the NVIDIA control panel. Just use the RTX4090_V2.1.exe update tool as it will include the changes introduced in V2.0.
i know i already did this BIOS update on my card but still it was black screening at idle.all power states are disable in Bios and also in windows.only prefer maximum performance in nvidia control panal solve the problem but then my card is in boost clock all the time even if i am not doing anything 😞 why asus release special bios for Z790 to fix RTX 4090 ? why cant asus not release for other boards ? does asus know this problem by the way ? can my card be faulty ? but if its faulty then it must give crashes in load not in idle ?
Regarding the idle black screen enabling the performance mode means always having the card with maximum voltages and frequencies.
That's why it works.
The defective chip fails to be stable under the low voltage of the idle state.
It's a workaround that shouldn't exist on a 2600 euro card.
It has to work perfectly out of the box.
The only solution is to RMA the card.
I had the same problem as you and wasted my time and money trying to fix it.
I sent the card to ASUS for assistance and they recognized the problem immediately without batting an eye.
They refunded me because they didn't have stock to replace.
I bought another 4090 Strix and it works perfectly.
Sadly there will be no magic drivers or special bios to fix a problem caused by a bad chip.
The card must work with all the drivers otherwise every update you have to rely on providence.
Is it still OK ?