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

[LongHiker]

@EmirTA Can you provide more information on the "high-resolution adapter"? Is it just a high quality cable or some type of device? 

[Ecto]

Happening to my new Tab S8+ and Monoprice USB Hub with HDMI that I got for Christmas as well. HDMI output is super low frame rate and very high latency, and tablet screen itself turns super low frame rate and high latency as well, making both unuseable. Hub is the Monoprice 6-in-1 usb-c multiport adapter. It does not require power to function.

[bill-e]

Reproduce the issue and then open the Samsung Members app, click on Support (Lower right)->Feedback->Send Error Report,  Remember to check on "Send System Data Log" 

[Ecto]

I just sent an error report as you suggested. Per your other comment, I do not have a way to connect my monitor via USBC. I guess I could get a USB c to HDMI cable but I shouldn't have to do that, a hub should work like they used to for lots of people before they stopped working.

I also turned on the frame rate monitor in the corner, and even while the monitor and tablet were laggy the frame rate didn't change so it wasn't properly representing what was happening on screen.

[bill-e]

What resolution/framerate were you getting out of that hub before the issue popped up? 

[Ecto]

I was never able to get smooth display out of the hub. It happened since the beginning of trying it. The resolution seems to be the full 4K of my TV, but the framerate on both displays drops to 10-15 it seems, with maybe 300-500ms of latency of touches.

[bill-e]

TVs tend to upscale to 4k. With a working hub I was able to get 2560x1440p and 1gE out of my Tab S8U vua the hubs hdmi port.

Everything plugged into the hub affects the video bandwith as neither thr tab 8 or 9 have enough out of the port to support 4k hdmi on the less expensive hubs and it yours is just doing hdmi with nothing else plugged into it then I'd wager that there is something wrong with it or it's a **bleep**. Neither of my working.hubs.were more.than 25$.

try a different hub and hope for 2560x1440p 60hz out of it using DeX or native resolution using mirroring.

[Ecto]

I just tried plugging into my computer monitor through HDMI with the hub and it still had the same issue. My monitor said it was receiving a 3840x2160 signal, though 1440p is the res of the monitor. I looked through all the settings on my tablet and didn't see an option for resolution.

So I guess I'll see if I can return this hub and try out a different one. Can you share the brand of the ones you have that work for you?

[bill-e]

First, boot to DeX on the external monitor.  Then from the external monitor open Settings->Samsung DeX->Display Resolution.  If your monitor supports 4k you will see it listed as an option but selecting it may not change the resolution.  Your hub, at best will do 4k30.  I would suggest trying one of the available 2560x1440 display options and see how that goes. 

Both of my hubs are now discontinued and no longer on Amazon.  Virtually any multiport hub with power pass through should work and you don't need to spend a lot on one.