I guess that is not about hardware ovc (e.g. CPU, GPU). It's about software ovc that is better known as speed hack. In general speed hack deals with system clock/timers by hacking system libs/dll files. Here you go: "They are used to speed up your system clock, because the game's communication protocols use synchronous data transmission. When the server attempts to synchronise with your system clock, your computer would be saying that a period of time, such as a second, for example, is actually faster than it should be and this allows you to move faster in online games if nothing is done to prevent it.

Speed hacks work generally for all games - they arn't just specifically built for UT2004. Lots of games have a ways of detecting them now, though, but at one time speed hacking was very potent. Almost every game and in every server I played, there was somebody zooming around. TFC HWGuys running faster than scouts and firing their miniguns as fast as lightning.

The original speed hack was not written to be a speed hack, specifically. It was some Chinease or Japanease program that was written to speed up your system clock, and some dude must have tried using it in an online game and saw that it worked. Then it spread like wildfire, unfortunately."