WD19TB cannot support 3x1440p, TB16 can, why???

Just received my WD19TB today, and happily replace my existing TB16. The additional USB-C is the main purpose i bought the dock.

However, I soon found that the WD19TB did NOT follow the description in Dell's official statement. I have 3x 2560x1440 display, they works with my old TB16, but NOT with WD19TB.


When the three 1440p monitors are connected with whatever port configuration, only 2 monitors will display at 1440p, the other one will drop to 1080p. There is no option under display property or Nvidia control panel for 1440p. Force resolution under Nvidia control panel did not work out. I somehow managed to get all 1440p with one of the monitor refresh rate dropped to 24Hz, and it must be connected to the Type-C TB (not the MFDP). However 24Hz is totally not acceptable.

Even when single monitor is connected to any of the DP/HDMI/MFDP port, the maximum refresh rate allowed is only 60Hz, whereas with TB16 it will allow up to maximum the monitor can support, in my case 144Hz, with whatever port plugin. Only the TB port on WD19TB will allow refresh rate up to maximum and only this port will support G-Sync.

I cannot find anyway to get triple display at 1440p 60Hz with WD19TB, this is unacceptable and Dell has promised with official statement that it can do so. Now i hook back to TB16 and happily get the 3x 1440p 60Hz working. Increase the refresh rate on TB16 above 60Hz (i.e. 85Hz) will work, but not that stable, the monitor may go blank occasionally with tripe monitor setup.

The firmware on WD19TB is the latest as at May 2020, and i really can't figure out what to do next. Anyone has similar setup that can advise?

 

Are you using this with your Precision 7720? WD19TB is only "supported" on 7X30 and up. I wonder if there is some firmware support needed to make it work properly with all of the edge display configurations...

 

Uh, yes it is 7720, but in Dell website 7720 is listed under supported model, 7710 isn't.

 

Ok, I didn't see that... I was looking at this spec sheet PDF which lists 7X30 but not 7X20.
https://www.delltechnologies.com/re...s/dell_thunderbolt_dock_wd19tb_spec_sheet.pdf
(Also pretty sure I saw a similar comment from Dell-Mano_G when these docks were first released.) Precision 7X30 got firmware updates specifically to support the 19 series docks... Haven't dug around in the 7720 firmware update history.

Would be interesting to see if there are any 7730/7740/7750 users out there with this dock and three 1440p displays to see if the issue can be reproduced. Three 1440p displays is a pretty niche case though and I think that there are more Precision users with the WD19DC dock.

 

You might try disabling DP1.4 / HBR3 support in each monitor's config menu if possible. Maybe an EDID / signaling issue with the newer MST hub in the WD19TB.

 

Do you mean the config menu in windows or the monitor built-in itself? I can't find this setting from both places anyway

 

Well, I managed to get triple output with 7720 by using 2 docks: E-port PR02X + WD19TB. Only 7720 can use this setup i think.
With whatever single TB dock, 7720 will need 2 steps to work: connect laptop power and TB3 cable. E-port + TB dock also needs 2 steps so there is no additional trouble.

Triple monitor setup will work with PR02X 1x DP + WD19TB 2x any port, all running at 1440p. The PR02X DP can set at 144Hz with G-Sync support, WD19TB remained 60Hz.

PR02X 2x DP + WD19TB (any port) will not work. Of course PR02X 2x DP + laptop mini DP works, but this setup has 1 more step trouble to connect TB3 network card, and lost USB-C connectivity.