Custom Resolution Utility (CRU)

[Dreamic]

(09-02-2022 03:16 AM)ToastyX Wrote:  

(09-02-2022 02:12 AM)Dreamic Wrote:  In order to lower my VRR/LFC Range from 80 to 30, changing it is not enough. I must also change the Device ID to something with a lower VRR Range, like DELA179 (Dell/Alienware AW2721D 1-240Hz). Mine is SAM105C (Samsung Odyssey G7 80-240Hz).
This is the only way to go below 80Hz VRR. Reset Device ID to SAM105C and it will no longer go down to 30Hz~.
Also the Nvidia database is wrong about this display being 60-240Hz, it's 80-240Hz.
Everything is as up to date as it could be, monitor firmware included.

That means NVIDIA must have ranges hard-coded in the driver for some monitors, possibly to work around issues like flickering. Does the ID need to be a monitor with VRR, or can it be any other random ID?

It can be any random ID, I just checked. It has to be a real manufacturer for CRU to let me click OK though, so I did SAM6666 which isn't a real monitor and my changes work. So it must be in the driver yes. I don't have any issues from doing this, I'm doing it to work around an issue that is flickering basically.

Obviously if I set the limit too low, issues will start to appear and get worse the lower you go, like flickering. Setting the limit to 30Hz makes LFC kick in around 39Hz or 39fps, where you will then be running 78Hz. At 40fps, 40Hz. I start seeing issues more around 35Hz and below, which would require me to set a limit of 25Hz~ or lower. Also playing games at this low of a framerate is not something I would do and already an unpleasant experience, but having to maintain above 80fps, higher actually as LFC kicks in above that, so lets say 90fps minimum, or my Hz will go from 90Hz to 178Hz if I drop to 89fps, there are visible brightness changes when this happens, flicker. Many games are comfortably playable down to far lower than this, LFC should not kick in until you drop below at least 60fps. These drastic Hz jumps are visible, doubling and halving. You want to minimize or eliminate how often it happens.

(09-02-2022 04:36 AM)aelius Wrote:  

(09-02-2022 02:12 AM)Dreamic Wrote:  I don't think it's a fault of your program but something dumb Nvidia is doing and I think should be added to the Editing VRR Range section, not sure if there's been discussion about this.

In order to lower my VRR/LFC Range from 80 to 30, changing it is not enough. I must also change the Device ID to something with a lower VRR Range, like DELA179 (Dell/Alienware AW2721D 1-240Hz). Mine is SAM105C (Samsung Odyssey G7 80-240Hz).
This is the only way to go below 80Hz VRR. Reset Device ID to SAM105C and it will no longer go down to 30Hz~.
Also the Nvidia database is wrong about this display being 60-240Hz, it's 80-240Hz.
Everything is as up to date as it could be, monitor firmware included.

I don't think everyone will figure this out, why their 40fps in GSync Pendulum is 80Hz instead of 40Hz or 70fps is 140Hz, it's because of Device ID, LFC doubling isn't changed unless Device ID is to a correct one.
And we know LFC on certain displays, I think I've heard mainly VA, results in a brightness shift/flicker, as Hz jumps from 75Hz to 150Hz etc when you drop to 75fps, 85fps will be back at 85Hz. This is how you fix/mitigate this.

Increasing the variable refresh range to dip down into 30Hz is a really bad idea, because the pixel response time and input lag will skyrocket, and if you ever dip below 30Hz the flicker will be way WORSE than before. There's a reason stock LFC kicks on as high as 80Hz.

A better approach is to shrink the variable refresh range. Flicker becomes harder to notice in the higher Hz, so you can leverage your 240Hz of headroom to make the range 120Hz-240Hz. Be sure to make it exactly 1/2 of the actual max Hz (239.something). You can go even smaller, if you like, but you'll create a gap in the coverage. A range of 150Hz-240Hz won't be able to engage variable refresh from 121fps-150fps, for example.

fwiw, flicker should only ever occur if you've got poor frame pacing, so the easiest fix is always to investigate why the game is running poorly. Many games are just unfixable though

You would agree with me if you were seeing what I'm seeing. The pixel response and input lag of this display are more than good enough 30-60Hz, and I won't dip low enough to engage LFC. Stock LFC being as high as 80Hz is rare, almost everything else is a good bit lower. I can still notice flicker too much in high Hz, I've thought about changing the range around higher like you're saying but for this display what I'm doing is a better solution. Lastly it's not poor frame pacing, it's LFC flicker, from engage and disengaging, doubling and halving your Hz up and down if you're hovering around and crossing the threshold one way then the other repeatedly, these doubling and halving of Hz fluctuations are very visible. Without LFC, your Hz up and down is just the same as your framerate up and down, you're not usually going from 80fps to 160fps in a millisecond etc. My understanding is this issue is more noticeable on VA VRR displays as well, maybe it's better with IPS etc, the brightness/flicker from huge Hz jumps.