OLED BFI question input lag vs clarity

[fLayN]

Hello

I wanted to be sure that I have understood well something about the BFI on OLED's.

1/ On Oled it adds black images instead of just turning off the pixels as for LCD, is that correct ? And that' why BFI on OLEDS split by half the max frequency of the monitor.

2/ So at 240hz/240fps BFI ON, it will LOOKS like 480HZ/480FPS, but the input lag will be the same as a 240HZ/240FPS am I right ? (which is minor but that's another subject)

Thank you very much

[RealNC]

1/ On Oled it adds black images instead of just turning off the pixels as for LCD, is that correct ? And that' why BFI on OLEDS split by half the max frequency of the monitor.

Yep. Except the pixels are not turned off on LCD. The backlight is turned off. It's the OLED that can turn off pixels, which is what it does anyway when you display a black image on it. If you load up a black image and make it full screen on an OLED, you just turned off all its pixels

2/ So at 240hz/240fps BFI ON, it will LOOKS like 480HZ/480FPS

Yep again.

but the input lag will be the same as a 240HZ/240FPS am I right ? (which is minor but that's another subject)

Only if the display uses QFT (quick frame transport) that makes the 240Hz mode scan out the frames at 480Hz speed, allowing it to show the black frame after after the content frame. If the display doesn't do that, the 240Hz BFI mode will have higher lag than normal 240Hz mode.

[fLayN]

Thank you very much @RealNC for those precious informations !

I found this thread about QFT very interesting viewtopic.php?t=8946

So maybe if I play a game at 240FPS (due to GPU/CPU limitation) on a 480HZ monitor :

#1 - 240FPS / 480HZ = Lowest input lag
#2 - 240 FPS / 240HZ BFi ON = Best clarity
#3 - 240 FPS / 240HZ BFi OFF (reducing the native Hz of the 480hz monitor) = better clarity but more input lag than #1 - worse clarity but butter input lag than #2

Thank you for the infos !

[RealNC]

#1 - 240FPS / 480HZ = Lowest input lag

Yes.

#2 - 240 FPS / 240HZ BFi ON = Best clarity

Yes.

#3 - 240 FPS / 240HZ BFi OFF (reducing the native Hz of the 480hz monitor) = better clarity but more input lag than #1 - worse clarity but butter input lag than #2

Same clarity as #1. No benefits to it over 480Hz if you use VRR. If you don't use VRR and want 240Hz vsync, you can still get that at 480Hz if you're on an Nvidia GPU by setting 1/2 vsync in nvidia profile inspector. You can choose between normal vsync (syncs to 480Hz,) 1/2 vsync (syncs to 240Hz), 1/3 vsync (160Hz sync) and 1/4 vsync (120Hz sync.) 480Hz with 1/4 vsync for example (to get 120FPS/120Hz sync) has quite a bit lower input lag than running at 120Hz mode with normal vsync.

But 480Hz with VRR is the absolute best when it comes to input lag, if the game you're playing doesn't result in too much OLED VRR flicker. Also note that if you use 480Hz, then no matter what FPS cap you use, when VRR matches the screen Hz to the game's FPS, it does so with QFT. So display lag will always be the minimum possible.

[fLayN]

I didn't know this trick with nvidia inspector, good to know!

Right I forgot about VRR, I use it only for single player games because I feel like it adds input lag on my LCD (27 G7 VA 240hz monitor) I know that you proved that it was not true but , but I can feel it more floaty, maybe it is not realy input lag but a motion feeling.

So yeah I'll give a try with VRR with an OLED for sure, I heard about the flickers when going quite low on FPS i'll keep an eye on that

Thank you very much very informative <3

[RealNC]

So yeah I'll give a try with VRR with an OLED for sure, I heard about the flickers when going quite low on FPS i'll keep an eye on that

Unfortunately it doesn't depend on going low on FPS. If the game has a frame time spike, even when FPS is high, it will flicker. Unreal Engine games for example that suffer from traversal stutter or shader compilation stutter will be very flickery. However, at 480Hz, I guess not using VRR is less of a problem. On my old 144Hz displays, there was a lot of judder without VRR. With the 240Hz OLED I have now, it's much less noticeable. The more Hz, the less visible the judder is when FPS doesn't match Hz. At 480Hz, I would imagine it being pretty hard to notice.

[fLayN]

Oh it's about the frame time alright. I play a lot of The Finals and it uses Unreal Engine so I'll check it out, but yeah as you say, such a high frequency without vrr isn't a real problem tho

Thank you very much again for the time spent to answer me