display goes blank

Hi there! I have a 1,5 year old system: Asus Rog Strix Z390-H i7-9700K, 4 x 8GB G.Skill Trident DDR4, Colorful 2080S Corsair TX750 LG34UC89G-B 9 (as primary display) Recently I have bought a second batch of RAMs, previously I had 2x8GB of the same Tridents. After I have installed them and...