Thank you! We have received the required details. We will work towards a resolution. In the meantime, you may also receive assistance or suggestions from the community members.

@akedna This article may help although it mentions Windows 8 I believe it applies independently of OS: https://www.dell.com/support/kbdoc/en-my/000132250/setting-up-multiple-monitors-using-intel-multi-display-option-in-windows-8

Hi @Vic384, thanks for the link, Multi-Display is enabled, as I see, if it wasn't, the integrated card won't even work. And being enabled, the integrated card via HDMI should be the primary one, but it is exactly the way it doesn't boot.

Let me explain. I only use one monitor and it is attached to the integrated graphics card because I get better performance using this card for graphics while using Nvidia one for calculations and computational matters.

But what @RoHe says in the thread you have linked may be the case: "When you have an add-in video card, at least one monitor must be connected to the add-in card before you connect a second monitor to an onboard Intel Graphics port."

The question now is: Why does a monitor have to be connected to the dedicated card to be able to boot? Isn't it something fixable? Once it boots with the Nvidia card I change the cable to the Intel card and both of them work perfectly.

@akedna 

@Vic384 

@DELL-Cares 

You dont need an actual monitor.  A fake one works fine.

Miners have this issue also.

https://www.amazon.com/Headless-Display-Emulator-Generation-Single/dp/B07FB8GJ1Z/

See

cryptominers fool nvidia anti mining with hdmi dummy plug

Thanks @speedstep for the tip, I think it will work, I have bought a fake adapter.

@RoHe, thank you for the comment too. I would like to clarify the performance issue. I have the Nvidia card running calculations and computational tasks. With the Intel video card output the speed of these tasks is always constant, but If I use the Nvidia video output, simply watching youtube videos or streaming the performance of the computational tasks drops sometimes significantly and sometimes I have received any strange error with some videos, probably because too heavy workload for GPU or using too much VRAM or something like this. I think letting this simple video work to the integrated Intel card which can handle it perfectly is fine.

I think it is a pity a computer can't boot the way I want, but I think it will work with @speedstep tip. I can consider this resolved, I'm accepting @Vic384 solution as the first one who told me it is mandatory to have the dedicated card attached to a monitor.

@akedna  - It was @Vic384  who mentioned one monitor needs to be connected to the add-in video card before connecting one to an on-board video port. That's correct. In the past, you couldn't use any onboard Intel Graphics port when an add-in video card was installed.

With newer processors Intel changed that so you can use both as long as one monitor is connected to the video card. Otherwise, you have to remove the add-in video card if you only want to use onboard Intel Graphics.

Doesn't sound right -to me- that you get better graphics from the onboard Intel Graphics than from an add-in video card, especially from a GeForce RTX 3060 Ti.  And keep in mind that onboard Intel Graphics uses system RAM and CPU time which can hurt performance, while an add-in video card has its own RAM and graphics processor to handle the load.

@akedna 

The reason you need a "monitor" is because windows needs to check which port the monitor is plugged into and get the HDMI resolution from the monitor.  So miners and people with headless servers in a rack with gpu need the "monitor" attached to satisfy the driver need to check which monitor is #1 for booting.  This is also why I use the dummy plugs instead of keeping my monitor on when I'm doing a big download.

@akedna - If you plug a "headless" adapter into the video card to allow booting with monitor plugged into onboard Intel Graphics, you will still have to unplug the adapter and move the monitor cable to the video card at some point, so I don't see what you gain by this...

How much RAM is installed in this PC? An i7 should be able to handle the loads even while using the NVidia card...

And how much useless junk is running in the background?

@RoHe I think I have misunderstood anything. I have understood that by plugging a monitor or a headless adapter into the Nvidia card the PC will boot, but I am making several tests now, and it is not the case if the Intel graphics card has another monitor plugged! I have to unplug the cable from the Intel card to be able to boot. Does it make sense? Can't I boot a PC with a monitor attached to the Nvidia card and another one to Intel one?

About performance issues, I think that useless junk in the background as you say is a very important factor, maybe 300 browser tabs, and one or two virtual machines are usually running at the same time, so despite having 80 Gb RAM and not filling them, I think somehow making the Intel vcard work for video letting Nvidia one for calculations works better. But it is annoying to change cable every time a reboot the pc

Is Multi-Display enabled or disabled in BIOS setup? You should enable it when separate monitors are connected to both Intel and NVidia.

Did you check/change settings for Primary Display in BIOS setup after you power on with monitor connected to NVidia card?

Did you plug headless into NVidia HDMI, and a monitor into Intel HDMI and try to boot, with Multi-Display enabled and with the correct Primary Display setting?

Is your "calculations" software programmed to use the (NVidia) GPU for its work? Otherwise, why do you think the GPU has any role in this? 300 browser tabs and one/two VMs is a really big load, so it's no wonder your performance isn't so good. Browsers, notably Chrome, are huge hogs of system resources. You might try using a different browser.

You may also want to close a lot of browser tabs and/or VMs and/or go up to the max of 128 GB of RAM, though that still may not be enough to help.

BTW: Have you looked in Windows to see if it's recognizing all 80 GB and how much is free/available when you have 300 tabs and VMs running? 80 GB isn't one of Dell's validated RAM configs in XPS 8940. Doesn't mean it won't work properly, but better to check.

Start>Run>msinfo32.exe and click OK. Click System Summary at top left and scroll down right pane to check "installed physical", "total physical" and  "available physical" RAM.

And use CPU-Z (free) to see what speed the RAM is actually running at, and if it's using Dual Channel mode which is faster and more efficient than Single Channel mode.
 

Multi-Display was enabled from the begining. But switching from Auto to Nvidia card in Primary Display has fixed the issue for me, I can now boot with headless display in the Nvidia card and the monitor in the Intel one.

I appreciate your comments about my hardware, the software uses Nvidia card without using the video output, 100% sure about this. I think the configuration of RAM is correct, but let me attach a screenshot in case you see something strange.

Glad you got that sorted. But you'll still have to move the video cable and the headless dongle, depending on which GPU you want to use. Would it just be easier to get a 2nd monitor for the Intel port?

How many browser tabs and VMs were running and was your calculations app also running when you checked RAM?  Out of the 80 GB installed, it says 33.5 GB is available so it was using 42% of RAM when you checked. 

Have you checked the CPU and GPU temps? Any signs the CPU is being throttled down due to heat which will cut performance?

Are you using an SSD and/or HDD? Have you checked performance of those drives and free space available?