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PG278Q Monitor doesn't work with USB-C-to-DP cable

Talwyn
Level 8
Hi,

I have this PG278Q monitor and a USB-C-to-Displayport cable, running from a Lenovo X1 Carbon 7th gen with USB-C/Thunderbolt3 ports, but I can't seem to get it to work.

I can see in the monitor specs that HDMI-to-DP adapters aren't officially supported by Nvidia and rarely works (found in my search one exception with an active adapter (w/power)), but it says nothing about using one USB-C-to-DP cable (it's not an adapter, though I suppose it might work like one).

I can find several different cases where an Asus monitor worked with such a USB-C cable, even when it wasn't specified that it was supported, though nothing about my own specific model. I'm aware that G-sync won't work, but that's irrelevant to my case.

My laptop is fully updated with both newest bios, drivers and firmware (drivers/firmware for USB, thunderbolt and monitor included), USB-selective suspend is disabled, nothing in my BIOS is disabling the feature.

I'm guessing the monitor doesn't support USB-C-to-DP, but I'm hopeful and reaching out for solutions anyway.

Hope anyone can help!
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8 REPLIES 8

xeromist
Moderator
As far as I'm aware there is no special requirement on the monitor side. With a compliant Thunderbolt device and TB>DP cable you would be sending a standard DP signal compatible with any DP display. It's literally part of the TB spec that it uses the DP standard.

So my guess is that you have a bum cable or you are using a USB-C port without TB support. Some laptops have both so make sure the port you plug into has the lightning bolt next to it.
A bus station is where a bus stops. A train station is where a train stops. On my desk, I have a work station…

Talwyn
Level 8
The X1 doesn't have any USB-C ports that don't also support Thunderbolt3, though I've tried all ports just in case. As annoying as it might be to have a bum cable, at least that might mean there's still hope. Thanks. 🙂

The cable is 2m long, so perhaps I'll have some luck buying a shorter one, of a different manufacturer.

Anyone else out there have anything to add? 🙂

Talwyn
Level 8
Unfortunately, buying a shorter and higher quality Moshi USB-C to DP cable didn't help. It refuses to detect the monitor, though it finds the cable just fine. Anyone else out there with advice?

xeromist
Moderator
The only other thoughts I have is check with Lenovo to see if they have any recommendations and if your area is not suffering an outbreak see if there is a friend or local shop with a monitor you can plug into. That would help narrow if the monitor is failing or somewhere else in the chain.
A bus station is where a bus stops. A train station is where a train stops. On my desk, I have a work station…

Talwyn
Level 8
I've tested on several DisplayPort monitors. The laptop works on all of them with no trouble at all. I also contacted Asus customer support, and if I'd updated my drivers, they couldn't really help me with anything more. They suggested it might just be a compatibility issue. 😞 Looks like I'm not getting anywhere on this one.

Pheolix
Level 7
Are you running the monitor in 165Hz-mode or plain 144Hz? I have had similar problems myself where the thing started workin when I set the display input to 60Hz. In my case it worked up to 120Hz, but not higher, which was due to the cable itself.

Talwyn
Level 8
My model has 144Hz max, but setting it at 60Hz did not help, unfortunately. 😞 Any other ideas?

Talwyn
Level 8
Yay! :cool: I made another attempt by updating to Intel's newest drivers, and it worked! They are not (yet) officially supported by Lenovo, so I had to do a manual install, but the result is glorious! 😄 120Hz is max, btw, and 144Hz gives you a black screen.