Blur Busters Forums

Reviews for the ASUS VG259QM monitor say input lag spikes when at 60 Hz.

Does this mean if I play games that are locked at 60 fps I would experience higher input lag? Would this also be true for games where 60 fps is the best I can get?

Tyler wrote: ↑

04 May 2021, 13:31

Reviews for the ASUS VG259QM monitor say input lag spikes when at 60 Hz.

Does this mean if I play games that are locked at 60 fps I would experience higher input lag? Would this also be true for games where 60 fps is the best I can get?

No, these are two different things:

60fps at 60Hz = high lag
...on most 240Hz monitors (except a few like ASUS XG248 and the upcoming ViewSonic XG2431)

60fps at 240Hz = low lag
...on virtually all 240Hz monitors

So the moral of the story is to switch your device to 240Hz (something you can do with PCs, but not with consoles) even for your 60fps games.

Or simply use G-SYNC / FreeSync -- a good way to get low lag from low frame rate games (on 240Hz+ monitors).

Chief Blur Buster wrote: ↑

05 May 2021, 01:08

Tyler wrote: ↑

04 May 2021, 13:31

Reviews for the ASUS VG259QM monitor say input lag spikes when at 60 Hz.

Does this mean if I play games that are locked at 60 fps I would experience higher input lag? Would this also be true for games where 60 fps is the best I can get?

No, these are two different things:

60fps at 60Hz = high lag
...on most 240Hz monitors (except a few like ASUS XG248 and the upcoming ViewSonic XG2431)

60fps at 240Hz = low lag
...on virtually all 240Hz monitors

So the moral of the story is to switch your device to 240Hz (something you can do with PCs, but not with consoles) even for your 60fps games.

Or simply use G-SYNC / FreeSync -- a good way to get low lag from low frame rate games (on 240Hz+ monitors).

Thank you so much for the reply. I really do appreciate it. I want to ask this follow-up question if I may only so that I can better understand how this stuff works.

If I were to use G-SYNC / FreeSync for low frame rate games, wouldn't that set the refresh rate to 60hz creating the 60fps at 60hz scenario?

Tyler wrote: ↑

05 May 2021, 12:40

Thank you so much for the reply. I really do appreciate it. I want to ask this follow-up question if I may only so that I can better understand how this stuff works.

If I were to use G-SYNC / FreeSync for low frame rate games, wouldn't that set the refresh rate to 60hz creating the 60fps at 60hz scenario?

No, because

(1) Not all pixels refresh at the same time, see high speed videos of LCD refreshing. A normal 60 Hz screen takes about 1/60sec from the first pixel to last pixel to finish refreshing.

(2) G-SYNC / FreeSync behaves similarly to Quick Frame Transport (QFT). A "60Hz" refresh cycle is transmitted at max Hz (1/240sec from first to last pixel) over the cable, and refreshed onto the screen at max Hz speed (1/240sec from first to last pixel).

Pixels are delivered over a cable one pixel row at a time, and refreshed onto an LCD one pixel row at a time.

Traditionally, a refresh rate was always in sync with how fast the panel refreshed (from first to last pixel).

But in the case of G-SYNC and FreeSync, refresh rate and the time of individual refresh cycles (scanout time) is decoupled -- the scanout is always locked to maximum top-to-bottom sweep velocity (max Hz). No matter what the refresh rate (frame rate) currently is.