I have a Precision 3530 with Thunderbolt. Fully updated (BIOS, Thunderbolt FW, video drivers, etc.)

I am trying to use three monitors. In some combination or another between the dock and the HDMI on the laptop to get full resolution on all three.

It's 3 Viewsonics at 2560x1440.

Using just the dock, I am only able to get 1 at 2560 and the other at 1920. But reading the WD19 guide it seems that I should be able to get (PDF User Guide).

My understanding, which might be wrong, is Thunderbolt (HBR3?) should support 2 monitors @ 2560. I am using both DP ports. I don't have a USB-C DP cable, but if that's the ticket, I'll get one. But I am not sure at this point.

I think I can then just use the HDMI on the laptop directly and ave the bandwidth from the dock.

Did I misunderstand?