From Mehrdad N:
SwiftSearch is a lightweight program whose purpose is to help you quickly find the files you need on your Windows machine without ever requiring you to index your drives. Most search utilities that achieve similar speeds do so by indexing drives while the computer is idle, but because idleness detection is so difficult to get right, in practice they end up slowing down the whole system just to speed up search. SwiftSearch works differently: given administrator privileges, it completely bypasses the file system (only NTFS supported) and reads the file table directly every time, which speeds up search by many orders of magnitude. Typically searches yield full results in ~10 seconds or less, a significant speedup for many users.