AMD has uploaded a new performance driver for Rage, you can download it over here. Turns out the driver they published on Monday contained outdated OpenGL files which caused all sorts of trouble in Rage.
AMD Catalyst Rage Performance Driver Features:
Significant performance gains for single GPU configurations
Compatible with AMD Radeon™ HD 6000, AMD Radeon HD 5000 and AMD Radeon HD 4000 series of graphics products
Includes the latest OpenGL driver component for Rage performance optimizations