First up, it built a simulation engine to see what users of the product were really experiencing out in the world. It tested start-up and shut-down times, adding gadgets and documents, as well as what happens every time you make a change to the software.
The next step Google took may not make you overly happy. Google has asked the users agree to report problems back to Google. You can opt out if you wish, though Google really, really wants to know when its software screws up. It says, "If you have opted in, the system will send us anonymous diagnostic information about such events as crashes. In the new version, we improved this system to also detect and report situations where our product could be making your computer slow to respond."
It used beta testers to also see what happens with third-party plug-ins and Google Gadgets and found a whole set of problems that can arise. Google, "added a system that detects when a gadget is causing your computer to perform poorly, and asks you whether to remove the gadget. While we were at it, we added proactive security measures that prevent malicious gadgets from stealing information from other gadgets."
The net benefits? Google says that memory usage has been chopped by 50%. Google Desktop will quit five times faster and also boots faster.
Go ahead and download it for yourself here.