When a new GPU is installed and results in lower screen resolution and picture quality, it's often because the appropriate OEM (Original Equipment Manufacturer) drivers for the GPU have not been installed. Without these drivers, the operating system may revert to generic drivers that do not fully support the GPU's capabilities, leading to suboptimal performance. Installing the correct OEM drivers should resolve the issue and allow the GPU to function at its intended performance level. References: * CompTIA A+ Core 1 (220-1101) Exam Objectives, particularly those relating to the installation and configuration of hardware components like GPUs, and the importance of installing the correct device drivers for optimal hardware performance. * General knowledge of hardware installation and the role of device drivers in ensuring hardware components such as GPUs operate correctly within a system.