Can't change refresh rate for external display

I am really so very tired of people like you spreading false information, and appalled when people actually believe what you're saying. Refresh rate DOES affect your display whether your using a CRT, an LCD, or even a plasma. The refresh rate is how many frames per second (hence using the Hertz measurement) that the video card sends to the display. Your LCD monitor cannot magically extract display information from your PC that was never sent. You saying that your LCD can display a 60 Hz picture when the PC is only configured for 30 Hz is like me saying that I'll sell you a gallon of gas out of a half-gallon container. It's ridiculous and you need to stop spreading false information. I have a TV that displays 120 Hz and when I create a custom resolution using advanced features in windows, and use the full 120Hz capacity of the TV, the fluidity of the motion is absolutely breathtaking. Mind you, this is not the 120Hz interpolation that you see on most TVs (although this TV is capable of that) this is a real 120 frame per second signal being sent from my PC to the display.

I am really so very tired of people like you spreading false information, and appalled when people actually believe what you're saying. Refresh rate DOES affect your display whether your using a CRT, an LCD, or even a plasma. The refresh rate is how many frames per second (hence using the Hertz measurement) that the video card sends to the display. Your LCD monitor cannot magically extract display information from your PC that was never sent. You saying that your LCD can display a 60 Hz picture when the PC is only configured for 30 Hz is like me saying that I'll sell you a gallon of gas out of a half-gallon container. It's ridiculous and you need to stop spreading false information. I have a TV that displays 120 Hz and when I create a custom resolution, and use the full 120Hz capacity of the TV, the fluidity of the motion is absolutely breathtaking. Mind you, this is not the 120Hz interpolation that you see on most TVs (although this TV is capable of that) this is a real 120 frame per second signal being sent from my PC to the display.

Not trying to sell anything, just help anyone here that might stumble upon your false information and accept it as truth. I came here looking for information to help me achieve a higher resolution rate and I found it. Maybe someone else can do the same if they make it past your false claims.

Probably because apple still doesn't have a refresh rate selection option in the settings and people like myself who are used to the smooth 165hz refresh rate on my windows powered lcd screen come to mac and get a laggy window dragging and gaming. So when you search on how to change it this is the first thing that comes up in google and your response applied to modern times is just out of wack and people don't get it.

anyway be nice if apple would just let me easily select my refresh rate.

No LCD screen needs a refresh rate. The screen is drawn/redrawn all at the same time. That setting is basically a hold over from the older CRT monitors that had color guns that needed to redraw the screen pixel by pixel.

Making any changes to the vertical or horizontal refresh rate will have no effect on the monitor you are using. So just forget about it.

quit you BS please

This is the help page:

$ cscreen -h

Usage: cscreen [-d <depth>] [-x <width>] [-y <height>] [-r <refresh>] [-s <display>] [-v] [-m] [-f] [-l] [-h]

[-d <depth>] : specifies the bit depth (bits per pixel)

[-x <width>] : specifies the width in pixels

[-y <height>] : specifies the height in pixels

[-r <refresh>] : specifies the refresh rate in Hz

[-s <display>] : specifies which display to use (defaults to main display)

use a as the option to -s to specify the action on all displays

[-i <displayID>]: picks a display based on CGDirectDisplayID (permanent per display)

continue to use '-s a' for "all displays"

[-v] : display valid modes (use -s to specify display or nothing for the default)

[-m] : require an exact match

[-f] : forces settings (ignores safety mechanisms; USE AT YOUR OWN RISK)

[-l] : lists the current displays and modes

[-p] : sets the requested display to have the menu bar

[-h] : displays the usage

Note: Using -p will change the display index so you will likely want to use -l again to show the current displays if you wish to use -p a second time.

First, use this to get a list of displays. Type in the command and hit the return key:

cscreen -i

this should change the refresh rate of the external display:

cscreen -r 85 "displayID"

As for why Apple doesn't honor that setting, you'll have to ask them.

You could also ask at the page I posted if what' I've posted above will work. I make no guarantees.

If created, then in /usr/local/bin/. Whether it's there by default is anyone's guess, since I might have created it years ago and it continuously migrates forward through the OSs. Alternatively, peruse the google hits for /usr/local/bin/.

Well because it can be used up to that refresh rate. I kind of miss poke, sort of. The refresh rate is the rate the screen is redrawn per second. All LCD screens are redrawn all at once not pixel by pixel as with CRT screens. Also a LCD screen does not go dark in between the redraws like CRT screen do. So even though they have a lower refresh rate then some CRT screen the image you are viewing never leaves the screen. With CRT screens if you used a camera, film or digital camera, to take a picture of the screen using a high shutter speed you would see part of the screen darker and without a real image on it. You caught the guns redrawing the screen and only part of the screen is visible during the time the shutter was open. The human eye doesn't work that fast so to your brain the image on the screen is complete.

Because of the higher resolution of a computer screens compared to a TV screen and the proximity of the person viewing a computer screen a refresh rate of 60 Hz could cause headaches and make the image look like it was moving, jumping or flashing at you. So most all CRT computer screens were able to have a faster refresh rate. The refresh rate is governed by the video card and it is not a independed rate for each monitor attached to the computer. So if you have a CRT screen that needed a refresh rate of 70Hz and above to make the image stable to the human eye and brain and also had a LCD screen connected in a dual monitor setup the LCD screen must be able to work with that faster refresh rate.

So your monitor Can Work Up To that higher refresh rate. It doesn't need it and it would do no good setting it to that higher rate. Also since there is no CRT screen attached there is no need for a higher refresh rate so that option is moot.

Ok now you have the rest of the story. For future reference do a google search for computer screenn refresh rate.

You are full of it. If you are not a knowledgeable electrical, computer or software engineering professional with current computing knowledge, don't spread false information online. People will take your words as truth for granted on this official Apple community form.

Thank you for your effort and cooperation.

This was the top result in Google when I searched for how to change refresh in OSX.

It's incredibly frustrating to see that the accepted answer is just laughably wrong.

LowLuster you should probably edit or remove your answer, because it isn't helping anyone.

Download cscreen, put it into /usr/local/bin, restart, and give that a shot via the Terminal app.