Performance pros with ATI/nVidia cards often use Omega drives in favor of ATI's or nVidia's own, because of the performance-oriented features of the Omega drivers. A new version for ATI cards has been released
, and is up on several mirrors available for download. It weighs in at 17.9MB, considerably smaller than either versions of the Catalyst package (the ones including the ATI CP). The primary purpose of these drivers is to give you access to a lot of non-standard features, in order to tweak your card just the way you want it. It isn't the most user-friendly way of doing things out there, and don't expect tech support to help you out, but for performance nuts, at least trying them once is a must.