Before you start yelling OMG FASTER WHO CARES??? you might want to read the fine article:
WHY A NEW DEBUGGER?
In order to achieve our goals we decided to start with a fresh architecture that would support modern multi-threaded programs, handle debugging symbols in an efficient manner, use compiler based code knowledge and have plug-in support for functionality and extensions. Additionally we want the debugger capabilities to be available to other analysis tools, be they scripts or compiled programs, without requiring them to be GPL.
This is about better code analysis and integration, not faster debugging.