CTO John Carmack took to twitter to announce that the Rift S has a lower pixel persistence than the original Rift, or even the upcoming Quest.
When the Rift S features were first released, many were shocked to learn that the refresh rate for this new product would be 80Hz rather than the usual 90Hz. This was generalized as a disappointment, but when it comes to virtual reality, refresh rate is only half the battle for a smooth display. The pixel persistence is a feature that is talked about much less, but is just as vital to a smooth experience as the refresh rate.
What Is Low Persistence?
Pixel persistence is measured by the amount of time per frame that the display is lit and not dark. Having low persistence is the idea of having the screen lit for only a small practice of that frame.
When looking around in VR, it is common to find scenes that look like they are smearing in a type of way. The reason? It is because the longer you are in a scene, the headset has a harder time tracking where you are and what you are looking at. Your brain is expecting the eyes to see the same as real life, with your view constantly changing as you are moving your head back and forth.
The usual approach (and one many companies have taken) is to up the refresh rate to decrease the time in each frame. It is not a bad idea and seems to be working pretty well, although there are better ways. Lowering the persistence is cheaper and works just as well, so Oculus has decided to take this approach with the Rift S. Lowering the persistence on this panel can have some of the same effects as a refresh rate as 500Hz. This is much more efficient than running VR games with 500 frames per second.
All high quality headsets have a low pixel persistence. This is an important feature to have smooth motion inside of games and experiences of virtual worlds. The Rift S, has a lower persistence and a lower refresh rate, which seem to be getting the job done in a great day.
Despite the Rift S having a lower refresh rate on paper than the original Rift, it should be delivering a less blurry and more smooth picture than its previous models. As you would expect, the two two features cancel each other out, and should be nearly unnoticeable when the common user puts the two headsets on to compare.
