This crack is designed only for all versions of WIndows XP SP3.
By increasing the number of TCP/IP connections allowed at one time, your internet speeds up, especially when you are downloading stuff or playing online games. I recommend you to set the limitation to 500 to 600.
Before applying the crack, remember to unplug internet connections and restart computer to make sure the TCP/IP file is not in use.
Download tcpip-patcher