Custom Resolution for External VGA Display

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Level 1

73 points

Custom Resolution for External VGA Display

I've been connecting an old display to my MacBook Pro recently via VGA (the DVI input on it is being used by my Windows PC) and have been annoyed to no end by the inability to set a proper resolution on the display.

I need the resolution 1440x900, which is what Windows is using over DVI and what the monitor's manual says is its maximum resolution. Unfortunately, the closest resolutions macOS will let me choose are 1400x1050 and 1344x1008, which are not only really bizarre numbers but stretch the image on the external monitor horizontally.

I've looked into several advanced ways to fix this, from the simple Option+Click on the "scaled" option in System Preferences to modifying display override files in the System directory. (I have a well above-average understanding of UNIX and macOS specifically, so I know what I'm doing; aside from, that is, this specific task which I have never had reason to learn how to do until now)

My question, then, is this: How can I set my own custom resolution in macOS Sierra for an external display? Every tutorial I can find online uses an older version of the OS before System Integrity Protection existed, and I'm not willing to install some bizarre third-party software like SwitchResX to get this done. I know this is doable in system files and at the command line, it's just a matter of knowing where to look. Can anyone help me with this? It would be greatly appreciated.

MacBook Pro (15-inch Late 2011), macOS Sierra (10.12.2)

Posted on Feb 20, 2017 4:17 PM

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Answer 1

TimsTech Author

Level 1

73 points

Feb 21, 2017 3:53 AM in response to dialabrain

I'm not an idiot, I know what a VGA connector looks like.

Not to mention that System Preferences flat-out calls it "VGA Display". You can see the resolution options for yourself.

I'm aware that 640x480 is a 4:3 aspect ratio, and that is what used to be common for VGA connections, but if my monitor can handle 1600x1200 without an issue then it should be able to handle 1440x900 which is fewer pixels than it is currently running. The monitor can also do both 1280x1024 and 1280x960, which are obviously different aspect ratios. When I said Windows is using the monitor at 1440x900 via DVI, I meant exactly that... my monitor has both DVI and VGA connections, and I am using the DVI connection for my Windows computer because my fancy GPU doesn't have a VGA port and I happen to have an Apple dongle that converts mDP to VGA.

I appreciate you trying to help, but I don't appreciate being patronized.

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Answer 2

TimsTech Author

Level 1

73 points

Feb 20, 2017 4:45 PM in response to dialabrain

I wasn't aware of that, and I can certainly look into it. Seems odd since I can use a higher resolution without issue (aside from the fact that it looks odd since its a higher resolution than the monitor supports) but I'm no expert on display technologies.

Despite that, I'd still really like to know how to force a resolution. If it won't work over VGA then I can revert the changes and use a slightly-lower resolution that supports the correct aspect ratio... which matters much more to me than maximum resolution, since I hate stretched images/videos.

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Answer 3

dialabrain

Level 10

136,025 points

Feb 20, 2017 5:50 PM in response to TimsTech

I have no idea what you mean. The VGA standard is 640 x 480 which is a 4:3 ratio.

From what you said above…

I need the resolution 1440x900, which is what Windows is using over DVI and what the monitor's manual says is its maximum resolution.

That would mean what you have is not a VGA monitor.

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Answer 4

Rudegar

Level 10

180,264 points

Feb 21, 2017 4:04 AM in response to TimsTech

the connector is called sub-D really, granted people often call it vga which is somewhat wrong, the cga/ega connectors only had 9 connectors and when newer 15 pins version that came out at the same time as vga resolution people somewhat wrongfully called the connector vga because the connector went as high as 1600_1280

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Answer 5

dialabrain

Level 10

136,025 points

Feb 20, 2017 4:30 PM in response to TimsTech

I might be remembering this incorrectly but VGA does not support a 1440x900 resolution. SVGA does if I remember correctly.

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Answer 6

dialabrain

Level 10

136,025 points

Feb 20, 2017 5:22 PM in response to TimsTech

FWIW, I believe VGA only supports 4:3 ratios but as I mentioned, it's been awhile. I'm sure the info i available.

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Answer 7

TimsTech Author

Level 1

73 points

Feb 20, 2017 5:29 PM in response to dialabrain

Kinda defeats the purpose of having a VGA port on a monitor that doesn't have a 4:3 Aspect Ratio...

Also doesn't explain why I can set it to 1920x1080. Let the painful research continue, I guess.

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Answer 8

dialabrain

Level 10

136,025 points

Feb 21, 2017 3:47 AM in response to TimsTech

I think we're talking about two different things.

https://en.wikipedia.org/wiki/Video_Graphics_Array

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Answer 9

dialabrain

Level 10

136,025 points

Feb 21, 2017 3:53 AM in response to TimsTech

TimsTech wrote:

I appreciate you trying to help, but I don't appreciate being patronized.

Sorry you felt I was being patronizing. It certainly wasn't my intention. I'll be on my way.

Good Luck.

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Answer 10

TimsTech Author

Level 1

73 points

Feb 21, 2017 3:58 AM in response to dialabrain

Thanks for your [first couple] posts. I've realized through all this that it's more trouble than its worth to get this figured out, unless anyone else sees this and has an easy solution I missed.

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Answer 11

dialabrain

Level 10

136,025 points

Feb 21, 2017 4:11 AM in response to Rudegar

+1

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