Hardware Unboxed recently conducted frame pacing tests on AMD's FSR 4 frame generation technology using a slow-motion camera, revealing severe screen tearing issues with FSR 4.
Frame generation technology works by inserting an AI-generated intermediate frame between two actually rendered frames, thereby doubling the frame rate. For example, a base frame rate of 60fps becomes 120fps output with frame generation enabled.
However, there is a key prerequisite: real frames and generated frames must be displayed in an even alternation, with each frame remaining on screen for roughly the same duration, for players to experience smooth 120fps. If the display duration of two frames is inconsistent, visible stuttering and judder will occur, rendering high frame rate numbers meaningless.
Hardware Unboxed used a slow-motion camera to capture footage frame by frame and discovered that when the RX 9070 XT had FSR 4 frame generation enabled, the display duration of real frames and generated frames was severely uneven, with one frame staying on screen for approximately four times as long as its adjacent frame. This means the generated frames flash by almost instantly, making the actual visual experience closer to 60fps than 120fps.
The tests covered multiple games, and none achieved a consistent frame pacing. God of War: Ragnarök, Cyberpunk 2077, Mafia: The Old Country, Assassin's Creed IV Black Flag Remastered, Resident Evil Requiem, Alan Wake 2, and Red Desert performed the worst. Borderlands 4 and LEGO Batman: Dark Knight Legacy fared slightly better, but issues persisted.
Enabling V-Sync does not resolve the issue either. Hardware Unboxed tested V-Sync combined with frame generation in some games, and there was no improvement in frame pacing.
Moreover, this issue does not appear to be unique to FSR 4. Reports indicate that AMD has had the same frame pacing defect since introducing frame generation technology with FSR 3, and it remains unfixed to this day.
