How can I increase the key repeat rate beyond the OS's limit?

In Windows you can set this with a system call (SystemParametersInfo(SPI_SETFILTERKEYS,...)).

I wrote a utility for myself: keyrate <delay> <repeat>.

Github repository.

Full source in case that link goes away:

#include <windows.h>
#include <stdlib.h>
#include <stdio.h>

BOOL parseDword(const char* in, DWORD* out)
{
   char* end;
   long result = strtol(in, &end, 10);
   BOOL success = (errno == 0 && end != in);
   if (success)
   {
       *out = result;
   }
   return success;
}


int main(int argc, char* argv[])
{
   FILTERKEYS keys = { sizeof(FILTERKEYS) };

   if (argc == 1)
   {
      puts ("No parameters given: disabling.");
   }
   else if (argc != 3)
   {
      puts ("Usage: keyrate <delay ms> <repeat ms>\nCall with no parameters to disable.");
      return 0;
   }
   else if (parseDword(argv[1], &keys.iDelayMSec) 
         && parseDword(argv[2], &keys.iRepeatMSec))
   {
      printf("Setting keyrate: delay: %d, rate: %d\n", (int) keys.iDelayMSec, (int) keys.iRepeatMSec);
      keys.dwFlags = FKF_FILTERKEYSON|FKF_AVAILABLE;
   }

   if (!SystemParametersInfo (SPI_SETFILTERKEYS, 0, (LPVOID) &keys, 0))
   {
      fprintf (stderr, "System call failed.\nUnable to set keyrate.");
   }

   return 0;
}

Many times I want to center a function in my window. Scrolling is the only way. Also, Ctrl-left/right can still be slow in code where there are a lot of non-word characters. I use keyboardking also. It has a couple of isssues for me though. One, it sometimes uses the default speed instead of the actual value I set. The other is sometimes it ignores the initial delay. I still find it very useful though. They said 4 years ago they would release the source in 6 months... :(

Ok, on the suggestion of someone that modified HCU\...\Keyboard Response, this works well for me.

[HKEY_CURRENT_USER\Control Panel\Accessibility\Keyboard Response]
"AutoRepeatDelay"="250"
"AutoRepeatRate"="13"
"BounceTime"="0"
"DelayBeforeAcceptance"="0"
"Flags"="59"

Windows standard AutoRepeat delay. 13 ms (77 char/sec) repeat rate. flags turns on FilterKeys? These values are read at login. Remember to log out and back in for this to take effect.

On Mac OS X, open the Global Preferences plist

open ~/Library/Preferences/.GlobalPreferences.plist

Then change the KeyRepeat field. Smaller numbers will speed up your cursor rate. The settings dialog will only set it to a minimum of 2, so if you go to 0 or 1, you'll get a faster cursor.

I had to reboot for this to take effect.

For Windows, open regedit.exe and navigate to HKEY_CURRENT_USER\Control Panel\Keyboard. Change KeyboardSpeed to your liking.