Microsoft's upcoming Windows Vista will allow users to add memory to the operating system through the use of USB memory keys, the company revealed at its Professional Developer Conference in Los Angeles. The option is part of a technology called Superfetch designed to make the next version of Windows faster to use over time. Superfetch will monitor the data and applications accessed by the user in recent months and preload those into its memory. This allows for faster access to data and applications. In current Windows versions the software loads applications and data only as the user asks for it. This takes time because Windows has to load not only the application itself after a system reboot but the drivers and other auxiliary applications. "Superfetch works great if you have a reasonable amount of memory, and it works fantastic if you have boatloads of memory," Jim Alchin, group vice president for Windows platforms at Microsoft, told delegates in Los Angeles. "But even if you don't have boatloads of memory, we have thought about that [with the USB option]." Superfetch adds the memory on the USB key to the system's virtual memory, which in turn is used to preload applications and data which the user accesses frequently. The USB option offers the ability to upgrade the system's memory even if there are no physical memory slots, allowing laptop users to increase system speed, according to Alchin. The user can still remove the memory key at any moment without affecting system stability. To prevent security issues, the information is encrypted on the key to prevent data leaks. Superfetch is one of several new ways in which Windows Vista is designed to increase system performance. Other technologies will automatically defragment the hard disk, and provide a visual tool to allow the user to spot possible bottlenecks in the system's performance.