HDMI Quirks

[highsky]

Yes, similar issue.

New laptops come with 1920 x 1200.

 

The issue occurs in duplicate mode.

 

What seems to be working, like it remembers the setting?

 

Open display settings, In Duplicate mode, Advanced Display, Select settings for the projector, Then advanced,
In display mode set this to 1920 x1080 

Select Keep changes.

 

If done by shortcut using nircmd tool doesn't seem to save changes.

 

 

[SamanthaD]

On 22/09/2025 at 17:27, DrBeaker said:

I don't recall VGA and it's subsets ever having as many issues/being as fussy as the 'future' HDMI standard has given us all. 😱

You're comparing apples with pears here. VGA was analogue, HDMI digital. When analogue signals get weak the signal is still there, just reduced and can be reamplified easily. When digital gets weak the signal that defines the ones become zeroes, and nothing can be saved once that happens.

 

Bear in mind HDMI was never meant to be anything more than a consumer grade standard, used for short interconnects between DVD players and TV's. The main push was from movie labels because of HDCP (which VGA doesn't transmit) rather than the multi-channel audio and all the other stuff you're sold on - they just wanted to prevent piracy. It evolved though, and honestly HDMI is the wrong standard for the job. I think best we have right now is SDI as it has a locking connector and good over long distance, or maybe HDBaseT.

[mrstrong]

bump... "Can anyone recommend a reliable 10m HDMI cable / manufacturer ?"

 

somebody mentioned fibre earlier, how about amazon basics ?  https://www.amazon.co.uk/Amazon-Basics-Braided-High-Speed-Fiber/dp/B0BYD8BWP2

or a standard one from KabelDirekt (same-ish price) they seem to have good reviews.

https://www.amazon.co.uk/KabelDirekt-7-5m-22-5m-German-Engineered-Supports-Ethernet-Black-Blue/dp/B004XJC6ZG

 

I only need 1920x1080 at 60hz duplicated 

[altecsole]

This one is HDMI 2.1 and support 8k - https://www.amazon.co.uk/Southlight-Cable-High-Speed-48Gbps-Supports/dp/B0CQK7F3GH/ref=sr_1_1?crid=28JX6MFVJ8TRR&dib=eyJ2IjoiMSJ9.df2yBRnbyA67R-4SF92Ue5UrDKsyK5Itd0M_MRSpiElNdAXtfiX5yIj_8-d3t6a9OGKgLZGdM_Ruu_V5u-r3nlvADWRnGmHIdIo0R4GpkakxvWRiMEoKiGSia7O5hRKmA6BM4IXw4x2W8GpBsgXNztCD88eSDfphZ2FO-pDIcEML3kYWhYjvdfP08NEGCP0ACv0gF8lOomQIewvqTTH-UwYZ3fcFbLyrB8QHXB3CfJ55mBFqkekalFJ3yGlTQPKrmaZkTM9BWaIib65FVTokOMXZMz7I4sFbepUM6To3Vmk.Z7_0aFJqIJ4uWoRvw5rd3nDt1Oe6lthMVJlVJECozpI&dib_tag=se&keywords=8k%2Bhdmi%2Bcable%2B2.1%2Bcertified%2B10m&qid=1758800316&s=electronics&sprefix=8k%2Bhdmi%2Bcable%2B2.1%2Bcertified%2B10m%2Celectronics%2C93&sr=1-1&th=1

 

[psydii]

1 hour ago, mrstrong said:

bump... "Can anyone recommend a reliable 10m HDMI cable / manufacturer ?"

 

somebody mentioned fibre earlier, how about amazon basics ?  https://www.amazon.co.uk/Amazon-Basics-Braided-High-Speed-Fiber/dp/B0BYD8BWP2

or a standard one from KabelDirekt (same-ish price) they seem to have good reviews.

https://www.amazon.co.uk/KabelDirekt-7-5m-22-5m-German-Engineered-Supports-Ethernet-Black-Blue/dp/B004XJC6ZG

 

I only need 1920x1080 at 60hz duplicated 

You may only need that, but if either end point supports higher, you may encounter issues with cabling that isn't in spec for the highest standard the end points support.

Amazon Basics used to do a 10m that worked well *for us* in cases where nothing short of a Bluestream would. I can say that with certainty because we ran out, and they stopped selling them, and the *only* thing that worked were the copper 10m bluestreams. However it seems Bluestream also stopped selling 10m copper too, so we (along with everyone here who needs it to work now and into the future with higher capability devices) moved to Active Optical Cables.

[EDIT BECUASE I DIDN'T READ IT PROPERLY - The new one from Amazon is a AOC, not copper] If that new Amazon one is as good as the old  one (it looks completely different), then it will be great. But it is different, so I can't endorse it, but I will say that it's worth a shot. Looking at the business ends, i wouldn't be surprised if it uses some active amplifaction/signalling to work - in which case, if it doesn't have a usb option for it to get its power, you may find inconsistent performance between devices / firmware / drivers. [Our AOC ones all draw power from a USB port on the board. So this probably needs to as well.]

Finally, I would be sceptical of any brand that sells 15m 4K/60+ copper HDMI as this at the ragged edge of plausibility and vendors that trade on the reliability of their cabling do not sell such products.

Edited September 25, 2025 by psydii

[gpjt]

Are others also experiencing these issues?

 

We've bought in a number of refurb units and moved to Win 11 and have put these kind of issues down to the new units aren't able to output to an IWB consistently after many hours of troubleshooting. 

 

What steps have you taken to get to a resolution? 

 

New cables (HDMI)

Adjusting refresh rates?

[Scan099]

Found with the longer cables you need to change the frequency of the refresh rate - ours were set to 60hz but dropping this to 30 and the screens work. 

 

I am sure if we paid for the more expensive longer cables we would not need to drop the refresh rate but it works for us.

[itskdog]

3 hours ago, gpjt said:

Are others also experiencing these issues?

 

We've bought in a number of refurb units and moved to Win 11 and have put these kind of issues down to the new units aren't able to output to an IWB consistently after many hours of troubleshooting. 

 

What steps have you taken to get to a resolution? 

 

New cables (HDMI)

Adjusting refresh rates?

 

My first step is usually to reduce the refresh rate from 60p down to 50i or 30p if possible. Deals with it 90% of the time.

 

If that doesn't sort it, I typically install the Intel Graphics Control Panel and switch to a compressed standard like 4:4:4 or 4:4:2 and see if I can disable GPU scaling to let the display handle it.

Edited October 1, 2025 by itskdog
clarify a sentence

[supportman]

We are also moving towards HDMI and USB-A direct to a USB-C dock. Then a short USB-C cable to laptop.

 

Means single cable touch, display and power to all laptops.

 

The hub needs to be powered, but it eliminates all the refresh rate issues from our experience.

Edited October 3, 2025 by supportman

[gpjt]

Further to adding to the thread a little while back these issues have us pulling our hair out with no consistency and it simply not making sense. We have one Promethean panel that just won't stay on consistency for the poor class teacher. We've swapped cables, PC's, rebuilds all on various devices.  I had a community alert off Promethean which sparked my curiosity to check their forums and low and behold found this thread

 

So there is a known issue which Intel and MS are working on right?

Edited November 7, 2025 by gpjt

[synaesthesia]

Interesting - I've suspected drivers/software handling has been at play for a number of years, as it was even reproducible across device brands with certain chipsets (but not limited to one particular type). Seemed bonkers that buying EDID emulators was literally the easiest way of working around the issue because trying to enforce resolutions & refresh rates on devices that move from board to board with 2 screens is just pointless. Fingers crossed something comes of this then!

 

Windows 11 (well, any Windows update really) does seem to introduce a few more quirks - WiFi signal strength on W11 devices is diabolical compared to the same device on Windows 10. 

[Brax]

6 hours ago, gpjt said:

Further to adding to the thread a little while back these issues have us pulling our hair out with no consistency and it simply not making sense. We have one Promethean panel that just won't stay on consistency for the poor class teacher. We've swapped cables, PC's, rebuilds all on various devices.  I had a community alert off Promethean which sparked my curiosity to check their forums and low and behold found this thread

 

So there is a known issue which Intel and MS are working on right?

Nah need to implement copilot into more things first.