Hi James Lloyd,
It sounds like you were trying to optimize your PC's performance, which is always a good idea. The "graininess" you are seeing is actually a very common side effect of Windows or your graphics card trying to save system resources by disabling font smoothing or dynamically adjusting contrast.
To get your crisp display back, let's first check the Windows visual effects. If you open your Start menu, search for Performance, and select Adjust the appearance and performance of Windows, you'll likely see it's set to "Adjust for best performance." Simply changing this back to "Let Windows choose what's best for my computer"—or at least ensuring that Smooth edges of screen fonts is checked—usually fixes the graininess immediately.
Since you specifically mentioned an "adaptive" setting, another place to check is your graphics control panel (like the Intel Command Center, AMD Adrenalin, or NVIDIA Control Panel). If you right-click your desktop and open it, look for power-saving features named Adaptive Contrast, Vari-Bright, or Display Power Saving Technology and turn them off. These settings intentionally degrade image quality to save power, which often results in a grainy look. It's also a good idea to quickly peek at Settings > System > Display > Advanced display just to confirm your resolution and refresh rate haven't been bumped off their standard, native values.
As a quick tip, if your screen looks clear again but the text still feels slightly off to your eyes, searching for and running the ClearType Text Tuner from your Start menu is a great way to recalibrate how fonts render on your specific monitor.
I hope this response provided some helpful insight. If it clarified the issue for you, please consider marking it as Accept Answer so others with the same issue can find the solution.
Tracy.