Refresh rate, VRR and ALLM
Matches refresh to the source's frame rate to stop tearing and stutter.
- Standard
- HDMI 2.1 VRR (feature), AMD FreeSync
- ISO 21118
- Extension
At 60 Hz a frame takes 16.7 ms to send. A display that shows each line as it arrives, so the bars read progressively later down the screen. With 0.0 ms of extra processing, the Leo Bodnar top, middle and bottom bars read 2.8, 8.3 and 13.9 ms.
A model of the Leo Bodnar tester's three bars: each reads the time from the start of the frame to light appearing at that height. The three bar heights and the 'extra processing' value are illustrative; blanking time is ignored. Reviewers conventionally quote the middle bar.
- Frame time
- 16.67 ms1000 ÷ 60 Hz
- Top bar
- 2.8 ms
- Middle bar
- 8.3 ms0.50 frames
- Bottom bar
- 13.9 ms
Show the numbers
| Frame time | 16.667 ms |
|---|---|
| Top bar (17% down) | 2.78 ms |
| Middle bar (50% down) | 8.33 ms |
| Bottom bar (83% down) | 13.89 ms |
How to compare it
Variable refresh rate
Rare on projectors. It's a real differentiator for PC and console gaming.
Auto low-latency mode
The source signals 'game' and the projector switches to its low-lag mode automatically.
A convenience feature. Low-lag performance is the thing that matters.
Standard: HDMI 2.1 ALLM (feature)
Deep cut
Variable refresh rate. Field-sequential DLP and pixel shift complicate VRR, because sub-frame timing is locked to fixed cadences.
Terms on this page
VRR (Variable Refresh Rate)
HDMI 2.1 VRR, FreeSync and G-Sync compatibility. Rare on projectors. ⚖ gaming.vrr
ALLM (Auto Low Latency Mode)
HDMI signalling that switches the display to game mode automatically. ⚖ gaming.allm