ClearType is disabled in Windows XP and enabled in Windows Vista, 7, 8, 8.1 and 10 by default. On different monitors, this has a different effect on how clear or readable text on the screen is. Generally, ClearType is more useful on LCD monitors.
In Windows XP and Vista, you can turn font smoothing and ClearType on and off; in Windows 7, 8/8.1 and 10, you can fine-tune font smoothing to your own requirements.
Here is how Windows XP looks on an LCD monitor with Standard font smoothing, ClearType font smoothing, and no font smoothing.
Here are the same examples for Window Vista.
And here's Windows 7 with ClearType enabled and disabled.
Generally, ClearType has a smaller effect on fonts in Windows 7 and newer, but you might still want to fine-tune ClearType settings to make text easier to read.
In Windows XP, right-click an empty area of Desktop and click Properties.
In Windows Vista, right-click an empty area of Desktop and click Personalize.
In Windows 7 and 10, open Start menu by clicking the Start button or using keyboard shortcut Ctrl+Esc. Type "cleartype" into Start menu search box and click Adjust ClearType text.
In Windows 8 and 8.1, use keyboard shortcut Windows Key+W to open Settings search, type "cleartype" into the search box and click Adjust ClearType text.
Touch screen users should swipe in from the right edge of the screen and tap Settings first.
In Windows XP, Display Properties window opens. Open the Appearance tab and then click the Effects button.
In Windows Vista, Personalize appearance and sounds window opens. Click the Window Color and Appearance link. This opens the Appearance Settings window where you should click the Effects button.
Select ClearType or Standard from the Use the following method to smooth edges of screen fonts box. To turn text smoothing completely off, clear the check box. Click OK in the Effects window and click Apply in the previous window to see the difference.
That's it for XP and Vista.
In Windows 7, 8/8.1 and 10, clear or tick the Turn on ClearType check box in the ClearType Text Tuner window. The difference will be visible on the screen immediately. Whether you decide to use ClearType or not, you will have to go through four (Windows 7) or five (Windows 8 and newer) additional steps in font smoothing adjustment for the changes to take effect, so click Next. Each step offers several text samples to choose from - select the one that looks best to you.
In case your device has multiple displays connected, you might have to adjust each one separately (recommended if the monitors are different models or brands) or choose the same setting for both.
After you've made your choices, a summary screen will be displayed. Click Finish.
And that's it for modifying font smoothing in Windows 7, 8/8.1 and 10.