Question My external monitor is stuck @ 30Hz

[maldido]

Hi,

First off excuse my english since it's not my first language.

I'm experiencing a weird issue when connecting my Dell Laptop to my external monitor, after one of the latest windows 10 upgrades it will only display with a 30hz refresh rate, although I've been able to use it for years at 60hz.

The laptop is a Dell Inspiron 15 - 7566, it mounts an NVIDIA GeForce GTX 960M graphic card, although the HDMI port is handled by the onboard Intel HD Graphics 530, these are the specs:

Processor Graphics‡ : Intel® HD Graphics 530
Graphics Base Frequency : 350 MHz
Graphics Max Dynamic Frequency : 900MHz-1.15 GHz
Graphics Video Max Memory : 64 GB
Graphics Output 4K Support : eDP/DP/HDMI/DVI
Max Resolution (HDMI 1.4)‡ : Yes, at 60Hz
Max Resolution (DP) ‡ : 4096x2304@24Hz
Max Resolution (eDP - Integrated Flat Panel)‡ : 4096x2304@60Hz
DirectX* Support : 12
OpenGL* Support : 4.4
Intel® Quick Sync Video : Yes
Intel® InTru™ 3D Technology : Yes
Intel® Clear Video HD Technology : Yes
Intel® Clear Video Technology : Yes
# of Displays Supported‡ : 3
Device ID : N/A

The monitor is an HP Pavillon 23 CW:

Display Type : LED-backlit LCD monitor / TFT active matrix
Aspect Ratio : 16:9
Native Resolution : Full HD (1080p) 1920 x 1080
Horizontal Refresh Rate: 80 kHz
Vertical Refresh Rate: 76 Hz

Now, the issue is if I set the monitor to a refresh rate higher than 30Hz (it should run at 1920 x 1080 60Hz) the screen blacks out, since I tried reinstalling windows 10 several times, I noticed that after a fresh install the image will hold at 60Hz for some time, then the monitor will go black although the signal is present and it's still recognised from the display settings.

I did perform some other tests in order to find the culript:

1 - The monitor will work as expected with my laptop if I boot it with Ubuntu on a USB key.
2 - The monitor will work as expected on another desktop with windows 7.
3 - The laptop will connect with a smart TV without any issue.
4 - The laptop will not connect with other monitors, a shop assistant made me the courtesy to try different ones from different brands.

I did contact Intel assistance and am waiting to contact Dell's one (the laptop's warranty expired) so far, from the tests I did I would exclude an hardware / cable problem, the culript seems to be windows 10, but it worked in the past and whatever new install I try (laptop reset with internal OS, cloud OS, USB key OS) the issue persists.

I did notice that after a fresh install, without connecting to internet, the OS won't recognize the external monitor at all.

I tried reinstalling the graphic Chipset driver from both Intel and Dell to no avail.
Did anybody else experienced similar issues?

Thanks.

 

[maldido]

An update, I've spoken with Dell assistance, they said the only option was to replace the motherboard which isn't available anymore, or to buy an external one.
Still I can't explain why the external monitor will work with Ubunto and I can connect to my smart TV with an ever higher resolution but still it won't work with any PC monitor.
Does this forum know is some SW exists to debug the HDMI signal?
[rant]I hate Microsofot so much, it's a racket, now and then they decide they must address a """security issue""" and will break things with their updates, thus perfectly working machines will be amputated or will need replacement (end in a landfill) so much for the green economy [/rant]

 

[maldido]

I want to give an update, I finally gave up and bought an USB/HDMI adapter, it works fine although playing videos is a bit laggy.
The issue is very similar as the one reported by Intel with its NUC hardware updates, although my motherboard isn't listed between those using these chipsets.


Summary
Troubleshooting steps for blank display issues after installing HD graphics drivers
Description
The Intel® NUC will encounter a no display issue on Windows 10 once it loads. This problem only appears when the HD Graphics driver is installed. Other OS such as Linux works fine.
The display is going blank randomly using the HDMI® port.

https://www.intel.co.uk/content/www/uk/en/support/articles/000036535/intel-nuc/intel-nuc-kits.html

Hope this is helpful, good luck.