Arbitrary refresh rates on 144 Hz Freesync monitor?

[Mizkreant]

I just recently bought an Acer VG271UP. This is my first high refresh rate LCD monitor. I notice that Windows only lists 60, 120, and 144 as the selectable refresh rates. Am I correct in assuming that since this is a Freesync monitor that supports a range of 48-144 Hz, that it is capable of displaying any arbitrary refresh rate within that range? It must, right? So if I create a custom resolution with a refresh rate of say 75 Hz, it should work fine? Can I damage the monitor if I enter incorrect manual timings? Should my graphics card be able to auto detect the right timings? Why are more refresh rates not exposed to the user?

[RealNC]

It should be able to switch to any arbitrary refresh you create. But it's not guaranteed. In VRR more it can refresh at any rate, that is true, but that doesn't mean the monitor's scaler can do that in fixed refresh mode too.

However, there's no need to add custom refresh rates with a VRR monitor*. If you want to play at 75Hz, you should still using 144Hz but just apply a 75FPS cap (with the in-game limiter, or if the game doesn't have one, using RTSS.) This will give you 75FPS. The scanout speed of the display is still as fast as 144Hz, which is why this is better than an actual 75Hz, which would only give you the scanout speed of 75Hz.

In general, the best refresh rate for the desktop is 120Hz and the best for games is 144Hz + the FPS cap you want.

(*Unless you're trying to experiment with custom refresh rates and strobing. VRR doesn't work with strobing.)

[Mizkreant]

(*Unless you're trying to experiment with custom refresh rates and strobing. VRR doesn't work with strobing.)

Yes, that is one of the reasons I was asking this. According to the manual (unfortunately the manual is not specific to this model) VRB works if the refresh rate is 75 Hz or higher. Running some of the tests here on Blur Busters at 144 and 120 Hz, the strobing mode produces an average amount of crosstalk. I can't test lower refresh rates because they aren't exposed in Windows. Experimenting with this is mostly academic as when playing games, I don't see myself ever not using Freesync. I can't tell the difference between Overdrive Off and Normal on this monitor, and Extreme causes massive overshoot.

Watching movies is another scenario I can imagine this helping. Would selecting a refresh rate that is a multiple of 24 Hz help reduce motion judder during pans? Or would Freesync be superior for this too? Does Freesync eliminate the need for 3:2 pulldown? I know SMPlayer supports Freesync.

[RealNC]

According to the manual (unfortunately the manual is not specific to this model) VRB works if the refresh rate is 75 Hz or higher.

Well you can just try it. It's easy enough to add new modes with ToastyX CRU. I never heard of damaging anything when using custom refresh rates. Whether or not the monitor will allow you to enable strobing though is a different matter. With g-sync displays, you usually need to do some vertical total trickery in CRU to allow ULMB in custom modes. On a 144Hz display that can do 144Hz ULMB for example, you'd use a high vertical total so that the pixel clock at 75Hz is the same (or as close as possible) to a 144Hz pixel clock. This usually allows ULMB to be enabled in the custom mode.

Watching movies is another scenario I can imagine this helping. Would selecting a refresh rate that is a multiple of 24 Hz help reduce motion judder during pans? Or would Freesync be superior for this too? Does Freesync eliminate the need for 3:2 pulldown? I know SMPlayer supports Freesync.

It depends on the accuracy of the video player. MPV is pretty accurate in my experience. This is why I say 120Hz is the recommended refresh rate for the desktop. It's a multiple of 24, 30 as well as 60, which are the most common video framerates.

[Mizkreant]

Well you can just try it. It's easy enough to add new modes with ToastyX CRU. I never heard of damaging anything when using custom refresh rates.

It depends on the accuracy of the video player. MPV is pretty accurate in my experience. This is why I say 120Hz is the recommended refresh rate for the desktop. It's a multiple of 24, 30 as well as 60, which are the most common video framerates.

Is doing this using the AMD driver not recommended for some reason? I don't know what all of these settings do. Time to do some research.

[RealNC]

Is doing this using the AMD driver not recommended for some reason? I don't know what all of these settings do. Time to do some research.

The GPU driver doesn't have any effect on this (unless you enable VRR, which as previously said doesn't make sense anyway since you should always use 144Hz for VRR.)

I also added some more info in my previous post about vertical totals.

[Mizkreant]

Oh, I meant using the Radeon driver to add custom resolutions/refresh rates.

[RealNC]

Oh, I meant using the Radeon driver to add custom resolutions/refresh rates.

Oh. I don't know. I never use the driver to do this. But through the driver should work as well.