Buying guide
Refresh rate, response time, input lag, and MPRT explained
Why refresh rate, pixel response time, input lag, and MPRT are different things, why “0.03 ms” is not total latency, and how strobing and “effective motion clarity” claims fit in.
Gaming monitor boxes mix several speed numbers that measure completely different things. Confusing them leads to bad buying decisions, so here is what each one means.
Refresh rate
How many times per second the monitor can draw a new image, in hertz. A 240Hz monitor can show up to 240 frames per second; each refresh lasts about 4.2 ms. Your PC must render that many frames to benefit, and variable refresh rate (VRR: G-SYNC, FreeSync, Adaptive-Sync) lets the monitor match whatever frame rate your PC delivers to avoid tearing.
Pixel response time
How long a pixel takes to change from one shade to another, usually quoted as grey-to-grey (G2G). OLED pixels change in a fraction of a millisecond; TFTCentral measured averages around 0.5 ms on several OLED models. LCD pixels are slower, and aggressive overdrive can speed them up at the cost of overshoot, visible as bright or dark halos.
A marketing figure such as “0.03 ms” is a pixel response claim. It is not the total delay between your mouse click and the screen.
Input lag
The delay the monitor adds before a new frame appears, from signal processing and scan-out. Good gaming monitors add very little: TFTCentral measured about 0.20 ms total display lag on the ASUS PG27AQDP and about 1.0 ms on the ASUS XG27AQNGV at 360Hz, rising by 2.5 to 3.5 ms with Pulsar strobing enabled.
End-to-end system latency, from input to photons, is a different measurement again; it includes your mouse, PC, game engine, and GPU. PC Gamer's 6.8 ms figure for the ZOWIE XL2586X+ is that kind of number. Never compare one outlet's end-to-end result with another outlet's display-lag result.
Motion blur and MPRT
Even with instant pixels, moving objects blur on most monitors because each frame stays lit for the whole refresh (sample-and-hold) while your eyes track smoothly. MPRT (moving picture response time) describes how long an image persists. Two ways to reduce it:
- Raise the refresh rate and frame rate, which shortens each frame.
- Strobe the backlight or insert black frames, so each frame is visible for only part of the refresh.
| Refresh rate | Sample-and-hold frame duration |
|---|---|
| 144Hz | 6.9 ms |
| 240Hz | 4.2 ms |
| 360Hz | 2.8 ms |
| 500Hz | 2.0 ms |
| 540Hz | 1.9 ms |
This table is arithmetic, not a measured blur score.
Strobing technologies
| Technology | Brand | Works with VRR? |
|---|---|---|
| G-SYNC Pulsar | NVIDIA (IPS monitors) | Yes, NVIDIA GPUs only |
| ULMB 2 | NVIDIA G-SYNC module | No, fixed refresh |
| DyAc, DyAc+, DyAc 2 | BenQ ZOWIE | No, per ZOWIE's US spec pages for current models |
| ELMB Sync | ASUS | Yes, per Tom's Hardware's XG248QSG review |
| BFI / ELMB on OLED | Various | Usually limited to specific refresh rates, without VRR |
“Effective motion clarity” claims
NVIDIA says G-SYNC Pulsar delivers “over 1,000Hz effective motion clarity.” That compares perceived blur with a hypothetical sample-and-hold display; the Pulsar monitors still refresh at up to 360Hz. Treat any “effective” figure as a perceived-clarity comparison, never as the refresh rate or the frame rate you will see.
What to look for
- Competitive play: high refresh rate plus either OLED response or good strobing, and low measured input lag.
- Everything else: response without overshoot, VRR that behaves well at your typical frame rates, and a good picture.