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I've just bought myself a nice external monitor for my laptop. My laptop's screen has a resolution of 1920 x 1080. The maximum resolution listed for my graphics card is 2048x1536. However when I plug in the external monitor, it lists resolutions up to 1600x1200, but not 1920x1080. 1600x1200 is no good as it's the wrong aspect ratio. What should I do?

edit

I'm using Windows 7 x64, the display is a Samsung Lavendar P2350

update

I downloaded and installed the drivers from Samsung (after much grief). The correct resolution is now listed, however if I select it the screen flickers unbearably, it is completely unusable. Any advice?

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What is the monitor -- and, more importantly, what is the monitor's native resolution? –  Chris_K Sep 28 '10 at 16:50
    
Monitor is a 24" Samsung, Native res 1920 x 1080 :-) –  fredley Sep 28 '10 at 16:51
    
Are there any drivers available from Samsung for your model? –  DMA57361 Sep 28 '10 at 17:06
    
Also might help if you provided the OS you are running, as display settings are set completely differently in Windows vs. Mac vs. Linux. –  Mistiry Sep 28 '10 at 17:15
    
@DMA No, the Hardware IDs declare it to be a standard Plug-n-Play monitor. –  fredley Sep 28 '10 at 17:30
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Check the refresh rate of your current graphics card and see if you can improve it. If you can't, it is most likely that you are at the limit of your GPU. It may be a maximum of 2048x1536, but that is for a single screen, not two.

2048x1536 = 3,145,728

(1920 x 1080)x2 = 4,147,200

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That limit is for the VGA out only, not for two screens... –  fredley Sep 28 '10 at 18:01
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@fredley, I think the point being made is maybe the card cannot handle two 1920x1080 outputs simultaneously. Have you tried using only the external and/or reducing the resolution of the built in screen? This is the same point I think jason404 was trying to make. –  DMA57361 Sep 28 '10 at 18:03
    
@DMA reducing the res of the main display does not work (the same resolutions reversed do). Although 1600x1200 works, 1600x900 does not. –  fredley Sep 28 '10 at 18:05
    
@fredly - "the same resolutions reversed do" - I'm sorry, I don't understand what you mean here, what resolutions on which screens? I thought you were aiming for 1920x1080 on both (so reversing would be the same), so I must of missed something... (as a side note, have you updated the drivers for the graphics card, as well as those for the screen?) –  DMA57361 Sep 28 '10 at 18:09
    
@Fredley - can you please just try to disable your laptop monitor and enable just the external one - I don't see anywhere that it says it can do both at 1920x1080 - it just says output... VGA output is just a saying for years - it means the "maximum output of a card" irrelevant of port - HDMI, DVI, VGA or other! –  William Hilsum Sep 28 '10 at 18:14
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If you're using VGA then one possible reason is that the cable was broken. I've seen many cases before on some PC, even after updating drivers the problem still appears. Just replace the cable and it's all gone

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Which laptop do you have, or more specifically, what graphics processing unit does it have?

The reason why you cannot use higher resolutions on your external display is because your laptop's graphics cannot handle so many pixels on two displays at once, either because of a lack of video memory or because the GPU is just not powerful enough.

This also happens with low-end discrete graphics cards and embedded graphics on desktop systems, and even on high-end cards, there is a limit to the display resolutions on multiple displays.

You cold try using lower colour depth to see if it helps, if it is due to a shortage of video memory, rather than processing power.

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I have an ATI Mobility Radeon HD 5470. In the linked specs, it lists the max resolution for the VGA output as 2048x1536 –  fredley Sep 28 '10 at 17:56
    
@fredley: That limit is for a single display and has to be shared between two screens. –  paradroid Sep 28 '10 at 18:05
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