Extremely Laggy HDMI and Dex Problem

[EmirTA]

Hello, I am having an extremely bad experience when I connect my Galaxy Tab S9 Plus and Tab S8 Ultra devices to an external display with a high-resolution adapter. The screen refresh rate of tablets suddenly drops and becomes truly unusable after connecting. I thought that the adapter might consume too much energy, so I tried while charging it, but nothing changed and there was no improvement. When I first bought my Galaxy tab S8 Ultra, I never had such a problem. But after an update, this problem occurred by itself. I am experiencing the same problem even with the Galaxy Tab S9 plus device that was released this year, and I would like to be informed about this issue and also I need to fix them as soon as possible

[Ecto]

Cool, I got a bit closer this time, but still not great. I guess since I was in the new Dex mode, I could only mirror, so switching back to the Classic allowed for me to have the extended display with Dex on it. It worked well on my computer monitor, and could choose the proper resolution for the display and the tablet still worked mostly smooth. 

But when I tried the same thing on my TV again, it made my tablet laggy, though not as laggy as before. Also there was no 4K option in the settings to choose, only 1080 and HD+. It seemed to be pretty smooth on the TV, but the tablet control and virtual mouse pad was iffy. It would register drags as touches sometimes, clicking on unwanted things, and there was a bit more latency on the tablet side of function as well. I guess I'll probably just give up on trying to use it on my TV, but if I change my mind on that, I'll just pick up another hub of some kind.

Thanks for your help!

[bill-e · Accepted solution]

Download Good Lock from. the Galaxy Store, from within it enable Multistar. Open Multistar and click on I Love DeX and enable Hi Res on an e ternL monitor. then reboot and try DeX Classic again.

[bill-e]

Did anything change recently, the hub or the cable? 

I use a direct USB-C connection to my monitor and don't havr any issues.  Does your monitor have a USB-C input that you can try? 

Also in Developer Settings you can turn on a framerate/resolution monitor.  Open Settings from the display that you want to watch and search on GPU.  It should return a GPUWatch setting in Developer Options.  Turn that on and a display will appear with the live video information.