Tweak Thumbnail Preview on Mouse-Over

Roll your mouse over an icon on the taskbar and wait a few fractions of a second, and you'll see a thumbnail preview of the exact contents of the corresponding window. Neat, huh? But you're impatient: You want your thumbnail to pop up the second you hover the pointer over the icon. As luck might have it, the Windows Registry offers a way to tweak this delay time.
In the Registry Editor, look for the following key: HKEY_CURRENT_USER\Software\Microsoft\Windows\ CurrentVersion\Explorer\Advanced. Right-click anywhere within the sidebar on the right, and select New, DWORD. Enter ExtendedUIHoverTime as the name. Double-click on your new value and replace the 0 with a 1, and change the Base to Decimal.