ATI will introduce Overdrive 4 with the next Catalyst Driver scheduled in March.This improvement will have to be done well in order to match the green team's very decent driver-based overclocking utility. There's some odd talk about a secure BIOS being required, perhaps to prevent modding, which techPowerUp! explains in its report.
Previously you could only overclock your GPU core with Overdrive, and only by a rather small amount. Now you can overclock both core and memory and the frequency range will be increased to 75% of the next higher class product.