Several media sources have reported that the KB5066835 update for Windows 11 has triggered a substantial downturn in PC gaming performance. According to tests carried out by Digital Foundry, computers outfitted with a Ryzen 7 9800X3D CPU and an NVIDIA RTX 5090 graphics card witnessed a frame rate decline ranging from over 33% to 50% while running Assassin's Creed: Shadows post-update installation. NVIDIA has rolled out a GeForce 581.94 hotfix driver to tackle the problem, whereas Microsoft has yet to issue an official statement.
