Dell dock vs regular USB C dock

Question

Can someone explain the difference between the WD19TB Dell Dock and a regular ~$80 USB-C dock sold on Amazon? They both seem to offer audio/HDMI/Ethernet etc. And the USB-C dock allows for charging via USB-C charger.

Am I missing something?

jphughan · Accepted Answer

@Jason5591  (You're quite welcome, happy to help....)  The 2020 XPS 13 is formally called the XPS 13 9300.  It is a DisplayPort 1.4/HBR3 system that supports Thunderbolt 3, and it would support the 'bonus features' I mentioned above when used with a Dell dock.  But it's also only a 45W system, which means it comes with a 45W power source.  So if you try to use that power source with some USB-C dock that provides power passthrough, the power it skims off will be significant as a percentage of total power available, and it will cause your system to complain about an undersized power source being connected and probably reduced performance.  So if you want to go that route, I'd connect the dock and power adapter to separate ports -- but that will usually means that any USB ports built into the dock itself won't provide much power, which could be a problem for running higher power devices like USB-powered external hard drives.  And even if you decide which of those tradeoffs you're ok with, you're still not comparing apples to apples.  The fairer comparison would be to price one of those docks AND an additional power source, preferably one with enough output that 45W will still be available to pass through to the system after the dock skims some off.  And then you need to consider the display(s) you intend to run.  If you don't have high end requirements there, you could maybe skip the WD19TB and get the less expensive WD19, in fact even the less expensive variant of the WD19, namely the 130W w/ 90W passthrough version.  You wouldn't need the WD19 180W w/ 130W passthrough since you have a 45W system.  That plus getting a decent USB-C power source for the other dock option narrows the price gap somewhat.  But if whatever dock you're looking at seems like it will meet your needs and you don't care about things like having an external system Power button on your dock, then go ahead and get that option.

jphughan · Answer

@Jason5591 It would have been helpful to specify the system you intend to use these docks with, but here's a start:

The WD19TB is a Thunderbolt 3 dock that is backward compatible with USB-C, not a USB-C dock. (The WD19 is the regular USB-C version.) But when the WD19TB is paired with a Thunderbolt 3 system, it can support dual displays up to 4K 60 Hz each, triple displays up to 1440p 60 Hz each, and even some quad display setups if the system supports that. A regular USB-C dock can support at most dual displays up to either 1080p or 1440p 60 Hz each, depending on whether the source system and dock support DisplayPort 1.2/HBR2 or DisplayPort 1.4/HBR3. The WD19 and WD19TB both support the latter if the system does. But some USB-C "mini-docks" only support a single display at a time even if they offer multiple video output connectors.
The WD19TB can provide up to 130W to an attached Dell system or 90W to a non-Dell system. If you have a Dell system designed for 130W, such as an XPS 15, then you'd want a Dell dock to run it because otherwise you'd have to either keep the power adapter attached separately (less convenient) or put up with performance throttling as you power your system from a dock that doesn't provide the full 130W. If you have some USB-C dock that supports power passthrough from some other USB-C source, then be aware that the dock will skim some power from that power source to run itself, so for example if you have a system designed for 60W and connect its 60W power adapter through the dock, you won't be getting 60W through to the system. Depending on the dock in question, the amount of skim can be 7.5 to 20W.
Dell docks come with their own power supplies. If you get a USB-C dock without one, then you have to continue tying up your existing power adapter there, i.e. you have to pack and unpack it every time you arrive at or leave your dock. With a Dell dock, the dock has its own power source, which frees up that power adapter up to be used elsewhere such as some other part of your home where you spend a lot of time or as a dedicated travel charger that lives in your bag so you don't have to take it out and pack it up every time you want to use your laptop at home.
Dell docks when paired with Dell systems that support these capabilities get some bonus features, such as the ability to use the dock's Power button to control the system. This allows starting the system up from full shutdown with the lid closed, for example. Dell docks can also support PXE boot and MAC Address Passthrough, but unless you're in an enterprise, those are unlikely to matter to you.

Hopefully that's a start.

XPS

Dell dock vs regular USB C dock

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