You have upgraded to Windows 8.1 from Windows 8, and noticed bad performance from your gaming mouse? More input lag and worse fluidity, even when dragging windows around on the desktop, not just in video games?
You’re not alone.
There is now a system-wide solution. Follow the KB 2908279 Instructions, install the hotfix (skip that step if already installed), and then add c:\windows\explorer.exe to your registry in Step #4. Although Explorer is not a game executable, this solution enables the high report rate (e.g. 1000Hz) system-wide from your gaming mouse in all your applications. This fixes all fluidity including window dragging, scrollbar dragging, etc.
UPDATE: Microsoft has modified the page.
You may have the Microsft update already installed. A better step by step:
Instead of C:\Program Files (x86)\Game\Engine.exe, enter C:\Windows\Explorer.exe
With this fix, your mouse will perform as well as it did under Windows 7 and Windows 8.
NOTE: If anyone from Microsoft is reading this, see Comments for scientific explanations why 1000Hz is better for window-dragging/scrolling, even on a 60Hz or 120Hz monitor.
Also, see the new Blur Busters Mouse Guide.