Last year, back before Google was conspicuously trying to cut costs in its phones, the Pixel 4 included a chip called the Pixel Neural Core. The special hardware ostensibly helped with a number of tasks like machine learning and always-on listening. But a look at the Pixel 5's spec sheet shows the Neural Core is nowhere to be found.
We know that Google likes to add auxiliary processors to its devices, like an extra image processor called Visual Core starting with the Pixel 2 and 2 XL. It's no different for the Pixel 4 and 4 XL which have received an additional Neural Core. Google says that they're using it to power the phones' face unlock and to speed up on-device processing, always-on listening, and machine learning.
Using your face to unlock your smartphone has been around a long time on Android, and it's used by many for its convenience over typing in a PIN or a password. With the right amount of lighting, it can even be almost as fast as fingerprint unlocking. Android's face unlock has suffered from some embarrassing mishaps, though, such as being fooled by a fake head or even just a regular 2D photo of your face. With the Pixel 4, Google is upping its game when it comes to face unlock security and speed. In addition to being secure enough now to process payments and log into apps, the Pixel 4 can recognize your face from any orientation, even upside down, and it does so very quickly.