instant on. It uses less time to get a reading. You may also want to research how radar works. I'm not trying to be mean, but I think it will give you a better understanding how it works. The big difference here is that with instant on, you can detect it. Sometimes it might be too late. Other times you can detect the blips...indicating a cop is using instant on. When their radar is in POP mode, most detectors can't detect the POP blips. That's because of the short sample they use. Now V1 has new code to pick up the POP blips. Then you can treat it like instant on.