Solve huge key lag in Windows 7 Qemu guest

Start, Run, “regedit”.
Tunnel to this key: Hkey_LocalMachine/System/CurrentControlSet/Services/i8042prt/Parameters
On the detail side, “other-mouse-click” a blank area and add a new Dword-32 value.
Name the key “PollStatusIterations” (no quotes)
Set value to Hex = 1
Caution, there are other registry keys with similar names.
Close Regedit and reboot.

If this value is already in the Registry, disable the key by renaming it to “xxPollStatusIterations” (Other-mouse-click, Rename). Reboot and test.