GPU usage and FPS plummeted 2.5 hours into flight

I have the same Problme like you:
Processor (CPU): Intel 10900k
Memory (RAM): DDR4 32GB PC 4000 CL18 G.Skill KIT (4x8GB) 32GVK Ripjaws
Mainboard: ASUS MAXIMUS XII HERO WIFI
Power supply: Corsair AXi 1600 Watt
Case: HAF X
Graphics card: ASUS ROG STRIX 3090
HDD / SSD: 1x SAMSUNG 970 EVO Plus NVMe M.2, 2 TB SSD, internal

  1. describe your problem. The more detailed and better you describe your problem, the better you can be helped(additional pictures could be helpful for example):

I have my 3090 for 2 weeks now. When I play MS Flightsimulator 2020 I start with Ultra 4K with about 43-45 FPS, after about 45-90 min the game starts to no longer 99% utilization of the graphics card, then the utilization always jumps between 55, 67, 76, 83, 91…n% utilization and my FPS thus fall into the basement below 30 FPS.

Now I also noticed that the 3 red lights above the PCI-E connectors are blinking. But I haven’t found anything about this on google search yet.

  1. what steps have you already taken/tried to solve the problem and what did it bring?

Restart computer, brings only briefly something

I have also used the search here in the forum, but found nothing.