Laptop lags when two external monitors are connected

[mjl6]

Hi!

Thanks in advance for taking a look at this post.

I am trying to hook up two external monitors to my work laptop. The laptop is a Dell Precision 5510 and is running Windows 10. It has two display adapters: an Intel HD Graphics 530 and a NVIDIA Quadro M1000M with 2gb GDDR5.

I am trying to connect two 24'' monitors. The monitors are: monitor one and monitor two. I am trying to connect one monitor to the HDMI port in my computer and the other to the usb-c port.

When I connect one external monitor, everything works as it should. It doesn't matter which one I connect, as long as its only one monitor everything runs smoothly. However, when I connect both monitors at the same time I run into issues. About every 3-5 seconds, everything becomes laggy and choppy for a couple seconds. It doesn't seem to be just the mouse lag, loading videos or anything else on my screen is impacted by this lag.

I've updated every possible driver that I can think of - both the video cards, the usb-c port, and BIOS. I've ran all the diagnostics from the Dell site informing me if I need to update any other drivers or if there are any other issues that might be wrong with my laptop. Nothing of significance came back. I've tried all different combinations of wires - displayport to usb-c, hdmi to hdmi, hdmi to usb -c, dvi to hdmi, vga to hdmi, etc (I have also double checked to make sure that the wires are the correct input and output) and rotated the different combinations between the monitors. I've also changed the resolution and colors on all three screens so that they are the same. And I've been restarting my computer between these attempts.

I would greatly appreciate if anyone has any feedback or suggestions they could send my way. Let me know if it would help to post any additional information about hardware/software.
Thanks!

 

[jensrobot]

I'm no expert, but i'm pretty sure if you plug a display in a USB-c port, it just forward the information to your motherboard/pcie bus.
As i understand it, usb-c can use "HDMI or DP alternate mode", but which graphics controller they are linked to i don't know. Maybe it's linked to onboard graphics, and this could make it slow and choppy, since essentially youre trying to sync 2 different graphic "cards" to one display.
It's still new for me, but i read recently that not all USB-c cables comply with official standards.
What brand is your usb-c cable?
And have you tried ONLY using usb-c for display and not hdmi?

 

[mjl6]

I'm no expert, but i'm pretty sure if you plug a display in a USB-c port, it just forward the information to your motherboard/pcie bus.
As i understand it, usb-c can use "HDMI or DP alternate mode", but which graphics controller they are linked to i don't know. Maybe it's linked to onboard graphics, and this could make it slow and choppy, since essentially youre trying to sync 2 different graphic "cards" to one display.
It's still new for me, but i read recently that not all USB-c cables comply with official standards.
What brand is your usb-c cable?
And have you tried ONLY using usb-c for display and not hdmi?

The two usb-c cables I have tried are usb-c and usb-c.

I only have one usb-c port and one hdmi port on my laptop so I can only use one at a time. Is it possible to change the graphics controller that the usb-c is linked to? I believe they are both linked to the intel hd graphics 530 - I was experimenting and I temporarily disabled this and both monitors shut off). Do you know if its better if each is linked to a different one?

 

[jensrobot]

Hmmm you have a laptop, so it's the same graphics card, I was assuming you had a desktop pc apparently 😀 totally my bad!
So never mind what i wrote, its not relevant to a laptop.
However can you answer me if your display works when only using USB-c?
Those are cheap cables, but they are not trash and should do fine. I have a usb-c 2 usb-c Choetech cable on order myself ^^