Refresh rates, what dictates them?

[DevilsHand676]

I was just thinking about it and why do monitors have these set refresh rates of 60, 75, 144, 165 or even 240. My monitor has the options of 144, 120, 119, 100, and 60.  Why am I given the option to pick, what seems like a random number of, 119 but not any number I want? What made manufactures choose 144 as the common gaming monitor and 60 for normal ones? Why not something more even like 150 or 50.

[Glenwing]

Standard for movies is 24 fps due to reasons back in the early film days, so all movies in the US are 24 fps.

 

60 Hz is the standard refresh rate for displays in the US because CRT displays used to use the frequency of the AC power from the electrical grid (which is 120 V 60 Hz) for synchronization. Europe standardized around 50 Hz for the same reason (and standardized around 25 fps for movies).

 

As the industry advanced, displays were made that did not rely on AC power frequency for synchronization, so they could choose other refresh rates. Many CRTs supported 72 Hz and 75 Hz, because it reduced the flickering effect that was visible at 60 Hz. 72 Hz was chosen because it is multiple of 24, for better compatibility with movies (just display each movie frame for exactly 3 refreshes, no complex gymnastics like 60 Hz requires to display 24 fps content). Likewise, 75 Hz is a multiple of 25 fps for europe.

 

Eventually we standardized around 120 Hz (5 × 24) and then 144 Hz (6 × 24).

 

In recent years manufacturers have stopped caring about multiples of 24 and 60, hence refresh rates like 165 Hz, which is just maxing out the available interfaces of the day (DisplayPort 1.2 in the case of 165 Hz).

 

As for why you have to choose from a dropdown menu; when monitors are connected, they send a file to the computer called the EDID, which is just a giant list of all the supported modes, as well as the name of the monitor and other things like that. Monitors explicitly list every single possible combination of resolution and refresh rate that they support, and those are the options that appear as options in Windows. And there are only a finite number of slots in the list, so they can't enter every refresh rate under the sun (and even if they could, no manufacturer would bother entering thousands of potential formats, 1080p 61 Hz, 1080p 62 Hz, 1080p 63 Hz... etc.). They just stick to the common standards.

 

However, the list is editable, so you can add whatever random refresh rate (or resolution) you want to it, and it will appear as an option in Windows. Just google for "how to set a custom resolution". But the hardware may be incapable of transmitting or displaying the format if you pick one too high, so you can't just enter 10000 Hz.

[Jurrunio]

18 minutes ago, Glenwing said:

 

Did you write this down somewhere else in the forums? So we can just throw links when similar questions pop up again

[Glenwing]

12 minutes ago, Jurrunio said:

Did you write this down somewhere else in the forums? So we can just throw links when similar questions pop up again

Nope, just here.

[Glenwing]

Also since I forgot to mention, the 24 fps standard was changed to 23.976 fps (24 / 1.001) when color film was invented (for some rather arcane technical reasons). People still call it "24 fps" though. The standard American refresh rates of 30, 60, and 120 are often changed by the same ratio, to 29.970, 59.940, and 119.880 Hz. Windows truncates numbers instead of rounding, so these will show up as 23, 29, 59, and 119 Hz in the menus.

[Jurrunio]

4 hours ago, Glenwing said:

Nope, just here.

Then maybe copy them to your display FAQ thread?