Be aware: if you have a console with either a weak PSU, several high current draw USB peripherals connected (USB HDDs, chargers) and/or capacitor problems, OC version will make your console crash with a red blinking light while playing some ps2 and ps3 games, since it puts extra strain on the PSU by increasing the power draw of the overclocked component, and the PSU shuts down to prevent damage. My slim console constantly crashed unless playing simple 2D games or emulating older consoles with OC installed, ever since I installed the non-OC firmware these crashes are gone.
@Evilnat you might wanna put a warning in the OP to reflect this, since these consoles are not getting any newer and the extra strain on the PSU might cause power problems.