Perform a clean driver installation using the Display Driver Uninstaller (DDU) tool to remove any remnants of previous drivers before reinstalling the latest version. Corrupted system files can also cause performance problems, so running the System File Checker tool (sfc /scannow) may help resolve any issues. Since you've recently unplugged your GPU to change your SSD, make sure the GPU is properly seated in the PCIe slot and that all power connections are secure.
Overheating can lead to performance throttling, so check the GPU temperature using monitoring software and clean any dust buildup if necessary. Additionally, updating your motherboard BIOS can improve compatibility and system stability. Power supply issues can also affect performance, so ensure your PSU provides adequate wattage for your system. Background applications may interfere with gaming performance, so try disabling non-essential programs, especially overlays.