The Finder’s search field, located in the toolbar, is hot searchable now. This means that the Finder starts finding as you type. It also defaults to all local disks, so this can get pretty slow if you have a ton of files.
In a Finder browser window, click the magnifying class icon to the left of the search field and hold the mouse, it is a menu. Choose “Selection” This will cause the Finder to only search your current folder and below. If you want to search an entire drive, just open the top folder 🙂 Of course you can always switch it back, but I like this as the default.