Questions about LFC for FreeSync Monitors

[sapped1]

Hey guys,

I’m hoping to purchase a new FreeSync monitor and just have some questions on the Low Framerate Compensation (LFC) feature.

I kinda have a special gaming situation here, I play Total War, Mount & Blade and Men of War extensively. I always run mods which triples the amount of troops on screen because I enjoy larger scale battles. Because of this I’m frequently bottlenecked by the CPU (already 4.7GHz OC) and runs below 30 framerate. It doesn’t really bother me though because I enjoy sitting back and watching the huge battles unfold. Hell, I even cap some of my games to 30 FPS to prevent wild framerate fluctuations.

This is also the reason why I’m really interested in this LFC feature, since my games run at 20-30 FPS most of the time. Although I just have some questions regarding this feature:

1) First of all if I understand correctly, LFC works to double the frames when the FPS falls below the monitor’s FreeSync range.
https://www.amd.com/Documents/freesync-lfc.pdf

So what happens when the FPS dips to a level that’s even lower than half the minimum refresh rate? (Say I only have 19 FPS in game, but have a 50-144Hz Monitor.) What does LFC do in this instance and does it still help smooth the frames somewhat?

2) Secondly I understand it’s possible to change the FreeSync range of a monitor using CRU. However will it be viable to underclock a monitor down to 20Hz so that I can still get FreeSync even in this low FPS range of mine? Or will underclocking the FreeSync range so low be damaging to my monitor?

3) And the most important question, what are some good monitors on the market that can allow me to underclock to 20Hz? Can’t seem to find much info on this, but I’d very much like to purchase a monitor and underclock it according to my gaming needs.

Anyway what are some of the monitors which would be most suitable for my situation? AOC G2460PF seem like a very popular option with a 35Hz minimum, but I’m not sure how well it can underclock and whether I can get it to 20Hz or not.

Thank you so much for reading this, I know it may be an unusual question, but I would very much appreciate any help and info that you can give.

Cheers and happy holidays!

 

[Sasqui]

LFC inserts staic frames between the missed frames when the PC can't deliver the FPS your monitor is able to display. Do you know what the frequency of the monitor at it's native resolution is set at for max? This is important, since the display cable may be the bottleneck depending on the card and monitor. 60hz is a typical max for 4k over DP, though you can get more with certain cables. In the end, for LFC you should max everything out and LFC should *help* minimize judder and tearing when the FPS drops below the optimal frame rate to your monitor.

Also, fill out your system specs!

Merry Holidays back

 

[eidairaman1]

Hey guys,

I’m hoping to purchase a new FreeSync monitor and just have some questions on the Low Framerate Compensation (LFC) feature.

I kinda have a special gaming situation here, I play Total War, Mount & Blade and Men of War extensively. I always run mods which triples the amount of troops on screen because I enjoy larger scale battles. Because of this I’m frequently bottlenecked by the CPU (already 4.7GHz OC) and runs below 30 framerate. It doesn’t really bother me though because I enjoy sitting back and watching the huge battles unfold. Hell, I even cap some of my games to 30 FPS to prevent wild framerate fluctuations.

This is also the reason why I’m really interested in this LFC feature, since my games run at 20-30 FPS most of the time. Although I just have some questions regarding this feature:

1) First of all if I understand correctly, LFC works to double the frames when the FPS falls below the monitor’s FreeSync range.
https://www.amd.com/Documents/freesync-lfc.pdf

So what happens when the FPS dips to a level that’s even lower than half the minimum refresh rate? (Say I only have 19 FPS in game, but have a 50-144Hz Monitor.) What does LFC do in this instance and does it still help smooth the frames somewhat?

2) Secondly I understand it’s possible to change the FreeSync range of a monitor using CRU. However will it be viable to underclock a monitor down to 20Hz so that I can still get FreeSync even in this low FPS range of mine? Or will underclocking the FreeSync range so low be damaging to my monitor?

3) And the most important question, what are some good monitors on the market that can allow me to underclock to 20Hz? Can’t seem to find much info on this, but I’d very much like to purchase a monitor and underclock it according to my gaming needs.

Anyway what are some of the monitors which would be most suitable for my situation? AOC G2460PF seem like a very popular option with a 35Hz minimum, but I’m not sure how well it can underclock and whether I can get it to 20Hz or not.

Thank you so much for reading this, I know it may be an unusual question, but I would very much appreciate any help and info that you can give.

Cheers and happy holidays!

What are your system specs please.

 

[cucker tarlson]

Wouldn't it be better to get a cpu that can hold 30 fps instead of a monitor that has LFC ?
Tell us what CPU you have, and a photo of your CPU usage in game.

 

[Cvrk]

I got FreeSync. Very confused about this to... i run my games throught Amd but if I don't have VSync on i see tearing. I researched this...and i still have my doubts . As far as i know FreeSync is activated between 45-70 fps, on my monitor. So i need at least a 45 fps...that is not a problem for what i play. I just don't udnerstand why i get screen tearing if i disable VSync.

 

[Apocalypsee]

I can answer #2 question. Yes you can lower Freesync range with CRU but it all depends on how low your monitor can go, and to some extent your cable quality.

I have 24MP59G which have 40-75Hz range, I could lower it to 33Hz on the bundled HDMI cable with the monitor although on cheap Displayport cable that I have cant even go below 40Hz. What happen is the monitor will be blank for few seconds and back on again back and forth until you exit the game.

I never read monitor could reach 20Hz minimum refresh, though I could be wrong. Usually people will overclock the monitor. My monitor cant be overclocked, perhaps LG block the firmware. At most it will do 77Hz.

 

[eidairaman1]

I can answer #2 question. Yes you can lower Freesync range with CRU but it all depends on how low your monitor can go, and to some extent your cable quality.

I have 24MP59G which have 40-75Hz range, I could lower it to 33Hz on the bundled HDMI cable with the monitor although on cheap Displayport cable that I have cant even go below 40Hz. What happen is the monitor will be blank for few seconds and back on again back and forth until you exit the game.

I never read monitor could reach 20Hz minimum refresh, though I could be wrong. Usually people will overclock the monitor. My monitor cant be overclocked, perhaps LG block the firmware. At most it will do 77Hz.

That is a nonstandard refresh rate as Standard is 60, 75, 85, 120, 144, 160...

 

[londiste]

1) When FPS dips below Freesync range, frames are starting to be doubled. If that still does not fit into Freesync range, it will get doubled again to make sure fps/frequency is in Freesync range.
From your example, game running at 19 FPS, each frame will get shown twice, resulting in 38 FPS/Hz for monitor. In case of a monitor with 50-144Hz Freesync range, that will get doubled again - each frame will get shown 4 times at 74FPS/Hz. It does provide the smoothing effect of Freesync but there is not much it can do for such low FPS.

2) Don't. Just, don't

3) There is no reason to underclock. Just go for a Freesync monitor with LFC.
I would stay far away from Freesync monitors that are not LFC compatible. And at that I would much prefer AMD's original definition not the new one - max refresh rate more than 2.5 times the minimum.

That is a nonstandard refresh rate as Standard is 60, 75, 85, 120, 144, 160...

I would argue that standard refresh rates are quite irrelevant especially in this thread where we are discussing adaptive sync
There is, however, a range for the refresh rates that monitor itself is designed/built to support and these do not go down very far. Generally that minimum is 30-40Hz and frame doubling (Freesync's LFC or GSync's inherent similar feature) is exactly what is intended to keep the refresh rate required from monitor above that minimum.

 

[qubit]

If you have a monitor refresh at 20Hz or lower (or the game engine puts out frames at this sort of rate) you're gonna get lots of judder regardless of what you do, so I wouldn't bother. Heck, one sees constant judder at a constant 30Hz anyway, just not as bad.

And yes, please do fill in your system specs. It's especially important that we know what CPU you have since it's quite possible that spending money on upgrading that will push up the overall framerate making for a much smoother render overall.

 

[INSTG8R]

That is a nonstandard refresh rate as Standard is 60, 75, 85, 120, 144, 160...

My FreeSync range is 35-90 but my monitor can do 144hz I keep it at 90.

 

[sapped1]

Hey guys, thank you all SO MUCH for your responses, sincerely appreciate this!

I’ve updated my system specs profile to include my CPU, as you can see there’s not much I can do to upgrade it further and I’ve gotten this CPU not too long ago as well, still thinking of keeping that.

Anyway I’m hoping to purchase a 1080p monitor, whether Displayport or HDMI would be fine although which would be better for displaying lower framerates? And looks like I won’t be underclocking to 20Hz haha.

Although for this instance, would it be better for me to buy a monitor which have 30Hz minimum or buy a cheaper one and then under clock it down to 30Hz? The 30Hz ones all have 144 or 120Hz as their upper limit and are quite expensive. But I’m not sure if I buy a cheaper option with 75Hz max, that I can tweak my lower limit to 30Hz or not.

Appreciate if you guys can recommend me a good monitor that’s suitable for my situation. Thank you so much again for your responses!

1) When FPS dips below Freesync range, frames are starting to be doubled. If that still does not fit into Freesync range, it will get doubled again to make sure fps/frequency is in Freesync range.
From your example, game running at 19 FPS, each frame will get shown twice, resulting in 38 FPS/Hz for monitor. In case of a monitor with 50-144Hz Freesync range, that will get doubled again - each frame will get shown 4 times at 74FPS/Hz. It does provide the smoothing effect of Freesync but there is not much it can do for such low FPS.

Ahh that’s really interesting, thank you so much for taking the time and explaining this to me in detail. So my original concern is no longer an issue since no matter how low the FPS drops (even single digits), FreeSync will still be active to provide smoothing.

By the way I’m really curious to know, what does a “doubled” frame look like in comparison with frames that’s “quadrupled”? Will the doubled frame look somewhat smoother than the one that’s displayed four times?
Cheers and thanks again londiste!

 

[eidairaman1]

You have an AMD card and a CPU that can feed it, Fire away with the Freesync monitor of your choice I say

 

[qubit]

I don't have a specific FreeSync monitor to recommend to you, but this is a great monitor review site which might help you to choose one.

www.tftcentral.co.uk

 

[londiste]

By the way I’m really curious to know, what does a “doubled” frame look like in comparison with frames that’s “quadrupled”? Will the doubled frame look somewhat smoother than the one that’s displayed four times?

It will be the exact same frame shown two or four times. There is nothing done with contents of the frame and there will be no smoothing here.
The purpose of this is purely technical - to get the required refresh rate into monitor's (or Freesync's) range.

 

[cucker tarlson]

I got FreeSync. Very confused about this to... i run my games throught Amd but if I don't have VSync on i see tearing. I researched this...and i still have my doubts . As far as i know FreeSync is activated between 45-70 fps, on my monitor. So i need at least a 45 fps...that is not a problem for what i play. I just don't udnerstand why i get screen tearing if i disable VSync.

Cause freesync must not be working in that case.
Try going into pc settings and disabling everything game bar or game mode related. I know it messed up the g-sync mode on my display. Although the monitor said it was in g-sync mode, the refresh rate counter showed 165, which would suggest it was not. I had minimal stutter and tearing, but still I am so used to playing with g-sync I noticed it instantly. Disabling windows game bar resolved it.