Launch regedit.exe and go to HKEY_CURRENT_USER/Control Panel/Accessibility/Keyboard Response. Change the values to the following:
AutoRepeatDelay 200
AutoRepeatRate 6
BounceTime 0
DelayBeforeAccounting 0
Flags 59
This will make your repeat delay/rate lower/faster than possible using the slider in the keyboard app. Feels great. May be bugged in windows 7, if so leave flags to default or upgrade your os.