Why can't I get refresh rates higher than 60Hz on my 100Hz monitor?

[r6mile]

Hello - I am using a 2018 Mac Mini, and have a Viewsonic 27" 2K monitor (https://www.viewsonic.com/global/products/lcd/VG2755-2K) that supposedly supports refresh rates of up to 100Hz. But I can't seem to get it to show any refresh rates higher than 60Hz?

I am using a brand new Benfei USB-C to DisplayPort cable that supports much higher resolutions and refresh rates. But the Mac OS Display settings don't give me the option of anything higher than 60Hz at 1440p. I have also tried SwitchResX, I set a refresh rate of 100Hz but it said it was "invalid" (it's also possible I used SwitchResX wrong as I haven't used it before).

Does anyone have any advice?

 

[Bigwaff]

Does anyone have any advice?

Might be setting in display onboard controls. Look for something called timing or refresh.

 

[r6mile]

Thanks for your response - I looked a bit deeper into the technical documentation and it turns out the Viewsonic promo page is incorrect, and the actual manual says the display only supports 60Hz.

 

[TumbleDryer]

Thanks for your response - I looked a bit deeper into the technical documentation and it turns out the Viewsonic promo page is incorrect, and the actual manual says the display only supports 60Hz.

Could maybe try and get a part refund for being mis sold.

 

[r6mile]

I am pretty sure the description on the website where I bought this from said 60Hz (I just looked at my e-mails), and it was 5 years ago anyway 🙂 Was not an issue as I was using a 2012 Mac Mini which doesn't support higher anyway, but now I'm on a 2018 so started looking into it.

 

[zarmanto]

Assuming you've correctly matched your product model to that linked promo page, that monitor should support 100hz, based upon the hype on the page; it would clearly be false advertising with a strong chance of an easy class action lawsuit, if it didn't perform as indicated. And you did your homework, it seems: even though the 2018 Mini did not "officially" support 100hz, the method that is supposed to work (unofficially) is exactly what you tried; a Thunderbolt 3 to DisplayPort cable.

The Google AI results I was just perusing seems to suggest that it might actually be a software issue, and that BootCamping into Windows could possibly yield better results. Have you tried that? Even if that's counter to your actual objective, (which I presume is using macOS at 100hz) it could at least narrow the scope of your debugging efforts.

 

[r6mile]

Good idea - I will try using Windows. It’s not a big deal as to be honest I’m used to 60Hz so might say I don’t know what I’m missing! (It might indeed be dangerous to try 100Hz as I may not be able to go back 🙂