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Vista upgrade slows down keyboard input

After an upgrade to Vista, keyboard input may be extremely sluggish. The culprit is a setting in the i8042 driver. Here's how to fix the problem.

Upgrading an existing XP installation to Vista will usually produce odd side effects that don't manifest when you perform a clean install. Clean installs of Vista, particularly on machines that came preconfigured from the factory with add-ons (such as the battery managers found in most notebooks), minimize conflicts with such things—although you'll have to either do without them or re-add them when Vista-compatible versions are made available.

One of the more immediately noticeable problems after an upgrade to Vista is extremely sluggish keyboard input. Typing may lag for seconds on end, and the CPU may register 100% usage momentarily while "catching up" from a burst of typing. In other words, typing slows down the whole system. Nor is the problem confined to any one application; it's endemic.

The culprit is a setting in the i8042 driver—the driver which controls the PS/2 port—which isn't correctly migrated during the setup process. One of the Registry settings for the i8042 driver controls how much of a delay time to impose after each keystroke; if this setting is lost, the delay time is set to 12 milliseconds by default.

To fix the problem, open the Registry and navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\i8042prt\Parameters. Look for a DWORD named PollStatusIterations; if one doesn't exist, create it. Set the value for the DWORD to 1, close REGEDIT and reboot.

Note: This problem only manifests with PS/2 keyboards, which always use the I8042 port device driver. USB keyboards are not affected, unless they're plugged into the PS/2 port via an adapter. Since notebook PCs often register the keyboard as a PS/2 keyboard, they may be particularly susceptible to this issue. Also susceptible: Wireless keyboards that use a PS/2 adapter.

About the author:
Serdar Yegulalp is editor of the  Windows Insight, (formerly the Windows Power Users Newsletter), a blog site devoted to hints, tips, tricks and news for users and administrators of Windows NT, Windows 2000, Windows XP, Windows Server 2003 and Vista. He has more than 12 years of Windows experience under his belt, and contributes regularly to and

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