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I have a laptop with the following relevant hardware:

  • Intel CPU with Intel HD Graphics 4600
  • Nvidia 940M GPU

I want to attach two Full HD monitors to this laptop. The laptop only has a single VGA port and a single HDMI port. The monitors support both these interfaces.

It is phsyically possible to attach a VGA and HDMI connector at the same time. So the laptop manufacturer did not intentionally block simultaneous use.

Would it be possible to:

  1. Attach both monitors and extend my desktop to these monitors without using the native laptop screen.
  2. Attach both monitors and extend my desktop to these monitors, also keeping the native laptop screen active (also Full HD).

I have not actually bought the monitors yet and cannot test the desired setup.

Thanks in advance!


I have found little to no information about the Nvidia 940M's capabilities to run multiple monitors through both VGA and HDMI simultaneously. The Intel integrated graphics card is advertised to support up to 3 monitors. A disclaimer at the bottom also states that mileage may vary...

I have found many discussions online about people wondering if their setup supports multiple monitors. But the information provided seems to differ wildly.

Related questions (oldest to youngest):


Edit:

I have bought the monitors and everything is working fine. I can extend the desktop to both external monitors and keep the native screen functional at the same time. This works both on Windows 8.1 and Linux (Ubuntu 16.04).

One side note: the quality of the image on the monitor connected through VGA is noticeably worse than image on the monitor connected through HDMI. As gronostaj has said in his answer: the VGA interface does not offer images as crisp as the HDMI interface.

  • Please edit your question to include the model / model number of your laptop. – Steven May 9 '17 at 17:43
  • Have you tried just connecting the monitors to the laptop? – Ramhound May 9 '17 at 17:48
  • @Steven The laptop was customized and purchased at BTO Notebooks. The model is called P-Book 15CL54. I can no longer find an online reference to the exact model. – Maarten Bamelis May 9 '17 at 17:48
  • @Ramhound I stated in the question: "I have not actually bought the monitors yet and cannot test the desired setup." I would prefer to simply try it but it would be an expensive experiment if it turned out my laptop only supports one external monitor. – Maarten Bamelis May 9 '17 at 17:49
  • You laptop is portable right? Why not just take it to the monitor store and test before buying -- to be sure? – Ƭᴇcʜιᴇ007 May 9 '17 at 19:56
2

It is physically possible to attach a VGA and HDMI connector at the same time.

Most likely yes. At least there's no reason to believe the contrary.

Would it be possible to:

  1. Attach both monitors and extend my desktop to these monitors without using the native laptop screen.

Yes.

  1. Attach both monitors and extend my desktop to these monitors, also keeping the native laptop screen active (also Full HD).

Also yes.

I have found little to no information about the Nvidia 940M's capabilities to run multiple monitors through both VGA and HDMI simultaneously.

It doesn't matter. In an NVIDIA Optimus setup (integrated + dedicated GPU) the Intel GPU is always driving outputs. NVIDIA chip is only used to render graphics. As you have confirmed, HD Graphics 4600 is capable of running with 3 monitors attached. Second source here.

Keep in mind that VGA cable won't offer image as crisp as HDMI cable, especially on high-resolution screens. It carries analog signal which is way more prone to interference than digital one and is degraded further by unnecessary digital-to-analog conversion on the output end and analog-to-digital on the input end.

If your laptop has native docking support (proprietary socket at the bottom), you may be able to get one more digital (ie. high-quality) output out of a docking station with no additional performance penalty. You can also buy a USB graphics adapter, but it will give your CPU a hard time and refresh rate may not be so great.

  • Thanks for all the information! - As the integrated graphics card is driving outputs, may I assume that both monitor setups would work equally well on Ubuntu? I am using both Windows 8.1 and Ubuntu 16.04 on the same laptop and would like to use the same monitor setup for both. Side note: I do not use graphically taxing applications on Ubuntu. – Maarten Bamelis May 9 '17 at 18:15
  • I don't know how stable HD Graphics 4600 is on Linux, but so far I've had better luck with Ubuntu on Intel GPUs than on NVIDIA. I think it should be stable, but it's just my guess. Maybe you could blacklist NVIDIA kernel module without breaking anything, it may improve power management and spare you installing NVIDIA drivers. – gronostaj May 9 '17 at 20:17

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