Below is a list of tools used for overclocking ATI Graphics Cards.
ATI Tray Tools
ATI Tray Tools is a small utility that can be found in the windows tray which then allows instant access to options and settings. Quite handy and quite a small download.
PowerStrip provides advanced, multi-monitor, programmable hardware support to a wide range of graphics cards - from the venerable Matrox Millennium I to the latest GeForce 6600GT and ATI X850.
As the name implies ATITool is an overclocking utility designed for ATI video cards. Design target is to write a light-weight application for the enthusiast - so no questionable registry tweaks.
Radlinker & Radclocker
RadLinker is a tweaker/linker for ATI Radeon based graphics cards (pretty much as the name suggests).
ATI Radeon BIOS Tuner (RaBiT)
Russian guru called Jaz has created a new BIOS editor ATI Radeon BIOS Tuner (RaBiT) with real ability to control Memory Timings (RAS-to-CAS, tRP, RAS#, CAS#, tRbs).
ATI Overclocking AntiProtection
A tool for unlocking that clock locked Radeon 9600 card.
Rage3D Radeon Tweaker
Rage3D Tweak is a multi-language Radeon Tweaker designed to fit right in with the other ATI option tabs in the Advanced Display Properties accessed through the Control Panel. It allows access to Registry Tweak options, Custom Display Modes, Refresh Rates, and Overclocking all through an easy to use interface. For those requiring instant access to all the tweak options, a handy icon on the task bar can be enabled for quick access to all three tweaker tabs. Comprehensive html, outline based help is available through the standard