Edit your registry: I am going to dispense with the cautions on care in registry and backup of it as if you are reading this, you should have some moderate to advanced knowledge of computers.
Open the registry and navigate to:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
On the right-hand side, you’ll need to find the key for DesktopLivePreviewHoverTime (or create a new DWORD if it does not exist) and double-click to edit it—just make sure to flip the Base radio button over to Decimal before you make edits (unless you think in hex).
The value is in milliseconds, so if you wanted 1 second, you would use 1000, or 500 for half a second, etc. If you want to make it instant, just set to it 0 (which works fine in hex too). The default value is 500, or half a second.
Making it zero (0) is okay too as this simply means there will be no delay. Having the registry entry present and with a zero is needed for no delay. If the registry entry was not present, the Aero peek defaults to half a second
Note that you’ll need to log off, and then log back on, for it to take effect.
Bonus tip for reading this far:
You can also increase the speed of the taskbar thumbnails which are displayed for running apps.
Add a DWORD at the same location as above (HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced) named: ExtendedUIHoverTime with a decimal value for the number of miliseconds.
When done, yours should like something like this - if you did both updates.
