What limits screen resolution?

[Balrog49]

1. Is the maximum resolution and refresh rate you can get on a computer limited by the graphics card, the screen, or both?

In other words, if I have a laptop with a maximum resolution of 1366 x 768 and an external monitor that supports up to 1920 x 1080, which is the maximum I can use? I'm wary of experimenting because I've had some test screens freeze a system, requiring a cold reboot.

2. I've observed that when the maximum resolution and refresh rate are different from the native or recommended resolution and refresh rate, the image looks like crap. Is there any way to work around that?

Sorry if these have been asked before but I've received conflicting answers and I need to understand how it works.

 

[rhysiam]

So a resolution needs to be supported by BOTH the graphics card and the display. The good news is that Windows (and any graphics card which supports multiple displays) will happily work with a variety of different displays running different resolutions all connected simultaneously.

So provided your laptop was released in the last decade, it should happily run the internal screen at 768p and your external monitor at 1080P at the same time. Alternatively, you can disable the internal screen and work solely of the 1080P monitor at its native resolution (1080P).

This is all assuming you're intending to "extend" your displays rather than "mirror" them. Extended displays is what most people use as it gives you more workspace. Mirroring does what it sounds like, displays the identical image on each display - and in that case it needs to output the identical signal (= same resolution and refresh rate) to both displays. That means running your 1080P screen at 768P or (if supported) running 1080P downscaled to 768P on your internal screen... and as you say, whichever screen is not running its native resolution will not look great.

So for extended displays - yes no problem... things get less ideal if you're trying to mirror.

 

[Balrog49]

So a resolution needs to be supported by BOTH the graphics card and the display. The good news is that Windows (and any graphics card which supports multiple displays) will happily work with a variety of different displays running different resolutions all connected simultaneously.

So provided your laptop was released in the last decade, it should happily run the internal screen at 768p and your external monitor at 1080P at the same time. Alternatively, you can disable the internal screen and work solely of the 1080P monitor at its native resolution (1080P).

This is all assuming you're intending to "extend" your displays rather than "mirror" them. Extended displays is what most people use as it gives you more workspace. Mirroring does what it sounds like, displays the identical image on each display - and in that case it needs to output the identical signal (= same resolution and refresh rate) to both displays. That means running your 1080P screen at 768P or (if supported) running 1080P downscaled to 768P on your internal screen... and as you say, whichever screen is not running its native resolution will not look great.

So for extended displays - yes no problem... things get less ideal if you're trying to mirror.

Thanks!

If I want to use the external monitor only, is the right way to disable the internal screen to open Control Panel -> Device Manager -> Display adapters, then select the adapter, right click, and choose Disable?

Just out of curiosity, if I disable the internal screen and disconnect the external monitor, will the internal screen come back on by itself?

 

[rhysiam]

No no, don't disable the display adapter, that's your graphics card. You still need that as it will be powering your external monitor.

It's likely that the laptop will immediately detect your external display once it's connected and powered, and usually will default to extended display mode. If that's not what you want, or it doesn't work, then most laptops have a key (sometimes you hold the FN button and press another key) to cycle between laptop display only, external display only and extended display (both displays). Check whether you have one of those.
If not, just right click on your desktop and choose "display settings" - everything you need is under there.

Just as a BTW, you should definitely give extended displays (using 2 screens at the same time) a go, it's super handy once you get used to it.