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For many PlayStation players, the arrival of PlayStation VR increased interest in purchasing a VR headset. High image quality and power consumption for PS VR games also put pressure on the PlayStation console's performance. VR's high hardware requirements have driven continued iteration. PS VR opened reservations for China on July 28, 2016, and sold out within hours. A few days later, PlayStation's China account on Weibo announced it was preparing a second reservation round.
PS VR's 120Hz specification stands out among current mainstream headsets, but the technical details behind that figure are important to understand.
Refresh Rate and Frame Rate
Refresh rate refers to how often the display is updated by the graphics output, for example 60 Hz means the display is updated 60 times per second. Frame rate refers to how many rendered frames the GPU produces per second, for example 60 fps means the GPU generates 60 frames per second. The display determines refresh rate while the GPU determines frame rate.
These two metrics are complementary. High and synchronized refresh rate and frame rate produce a better VR experience. An analogy: if the GPU can flip pages and the display can keep up with the flipping speed, the content is read smoothly.
Raising the refresh rate reduces rendering latency. Lower latency allows the image to follow head motion more closely, which helps reduce motion sickness.
As a console vendor, Sony prioritized higher refresh rates even at the cost of resolution to preserve smooth gameplay. In contrast, HTC Vive and Oculus Rift aim to support a broader range of VR solutions and workflows.
Advantages of a 120Hz Refresh Rate in VR Headsets
Most VR users have experienced motion sickness to some degree. Motion sickness remains a major challenge for VR adoption; mainstream headsets have not fully solved it.
Causes of motion sickness are multifactorial: human physiology, display refresh rate and frame rate, and the quality of VR content production all contribute. Among these factors, increasing display refresh rate is one of the most effective and directly addressable solutions.
Frame rate is a key metric in gaming, and the rise of VR has greatly increased its importance. HTC Vive and Oculus Rift target 90 Hz; Gear VR uses 60 Hz; PS VR can operate in several modes up to 120 Hz. In simple terms, higher frame rates and lower latency reduce motion sickness symptoms. High-end manufacturers often target 90 Hz as a baseline, while midrange solutions may use 60 Hz.
Consequently, PlayStation VR needed to deliver a competitive experience among the major headsets. Another design difference is that PS VR uses a single landscape panel split into two viewports, whereas many other headsets use two portrait panels. This implies Sony uses a slightly different optical and mechanical approach to handle IPD (interpupillary distance).
PS VR's panel resolution per eye is lower than HTC Vive and Oculus Rift. Lower resolution can increase the screen-door effect, especially on early prototypes, but resolution alone does not determine perceived clarity. PS VR's panel uses full RGB subpixel layout, which can produce better color and subpixel rendering than some panels that do not cover the full RGB gamut. Optical lens design and matching the lenses to the panel and field of view are also crucial factors affecting perceived image quality.
Is PS VR's 120Hz Refresh Rate Real?
PS VR achieves 120 Hz display behavior with assistance from Asynchronous Reprojection. This assistance is a deliberate technical approach rather than a deception.
PS VR supports three display modes:
Native 120 Hz
PS VR can run with a native 120 Hz display refresh rate, but this mode requires developers to optimize their applications extensively or the application itself must have low performance demands. In practice, that combination is uncommon.
Native 90 Hz, supported by a later firmware mode
90 Hz matches the refresh rate of HTC Vive and Oculus Rift. Sony implemented this mode to help developers target a more reachable performance goal. When an application can comfortably exceed 60 fps but cannot reach 120 fps, 90 fps is a practical compromise for developers.
Native 60 Hz converted to 120 Hz via Asynchronous Reprojection
A native 60 Hz application can be presented at 120 Hz using asynchronous reprojection. This approach attracted attention because it enables a higher perceived refresh rate even when the application cannot render native 120 fps. However, the technique has trade-offs, which is why Sony also offers the other modes.
Implementation of Asynchronous Reprojection
Rendering frames in VR is computationally expensive and time-consuming. VR requires tight latency constraints: if rendering takes too long and the image arrives after the frame synchronization point, the display must move on to the next frame and the user may experience severe motion sickness.
PS VR's 1000 Hz sensors provide new positional data every millisecond. Asynchronous Reprojection takes advantage of the fact that consecutive frames are often very similar. It uses minimal computation to generate a warped version of the most recent rendered frame that aligns with the latest head position. The user then sees this warped frame before the next full rendered frame is presented, temporarily compensating for head motion.
Asynchronous reprojection is "asynchronous" because the reprojection thread is separated from the main rendering thread. If both ran sequentially, reprojection would be delayed when rendering is slow, and the fixed frame sync points would make reprojection ineffective. In practice, reprojection means one frame is a true rendered frame, while the next frame can be a warped version derived from the previous rendered frame.
While asynchronous reprojection effectively mitigates insufficient frame rates, it is not a perfect solution and has its own limitations.
Conclusion
PS VR's 120 Hz refresh rate reflects Sony's product positioning and design choices; it does not imply other headsets are technically inferior. In fact, Oculus has significant experience with asynchronous reprojection and HTC has emphasized its use as well.
Nevertheless, a higher effective refresh rate produces a noticeable improvement in user comfort when implemented well. For developers, asynchronous reprojection is a fallback that helps preserve user comfort when the system cannot maintain target frame rates. When possible, optimizing applications to run natively at 120 Hz provides the best experience.
