replaced rams, mainboard, psu ... no improvement.
replaced CPU (some modell) - all fine now. so it seems I had a defective CPU that had serious problems with boost mode enabled
I'm asking for troubleshooting help, because I don't know how I should proceed with my build problem.
parts list:
cpu: Intel Core i9-9900K
mainboard: Gigabyte Z390 Aorus Pro
psu: be quiet! Straight Power 11 1000W
cooling: Enermax LiqTech II 280 (aio)
ram: Corsair Vengeance RGB PRO 4x8GB DDR4...