Kensington SD4900P Hybrid Dock Review

Kensington SD4900P Hybrid Dock Review

Kensington Computer Products may seem British, but this Californian technology company has existed for 35 years and manufactures a very wide range of personal computer equipment, including mice, keyboards, travel adapters and security mechanisms.

Today we’ll be looking at one of its docking stations, the SD4900P or the Kensington SD4900P triple 4K USB-C and USB 3.0 hybrid docking station to give its full title.

A product designed to improve productivity in the workplace by expanding a laptop to create a closer to the office experience.

But should the USB-C and USB-A connections exceed their practical limits?

(Image credit: Mark Pickavance)


Kensington manufactures a series of docking stations using a very similar package that includes the SD4700P, SD4800P and SD4900P which we are examining here.

Unlike some competitors who like aluminum cases, the designers of this equipment opted for injection molded plastic in black.

They also made some curious choices about the texturing of this case, where the top, bottom at the back and sides have a matte appearance, but the front is very shiny.

As we might have expected before opening the box, the shiny surfaces attract dust and fingerprints compared to the textured ones, which don’t.

Another slightly strange choice is that the top is slightly recessed, creating a sort of tray for a small change, or something else.

But as a docking station, the essential features are the ports, and the SD4900P has many.

On the back, a PSU power input, a computer USB-C downlink, three from DisplayPort 1.2 and HDMI 2.0, a Gigabit LAN port and four USB-A 3.1 Gen2 ports.

The ends are relatively unused, with a Kensington Security and Nano Security slot at one end and a power switch at the other.

And, at the front, a single USB-C 3.1 Gen2, another USB-A 3.1 Gen2, 3., a 5 mm audio jack for headphones and a 3-in-1 card reader that can manage SD cards, Micro SD and Compact Flash.

It’s important to note that although it is physically possible to connect six monitors to the docking station, DisplayPort and HDMI output are options, so you can choose three of the output that you prefer.

Our immediate reaction to this information was to ask ourselves why mounting six complex wiring ports on this device was a better option than providing three DisplayPort and some inexpensive cable adapters for HDMI?

We have to conclude that it was the cheapest option.

Another important external feature is two small threaded holes on the base designed to attach the SD4900P to the mounting bracket of the optional docking station (K34050WW).

(Image credit: Kensington Computer Products Group, a division of ACCO Brands)

in use

The big selling point of the Kensington SD4900P is that it supports triple displays and 4K resolution. But that immediately triggers certain alarms, because this docking station is not connected by Thunderbolt 3, and the USB 3.1 Gen 2 connection used has a quarter of bandwidth available.

No matter how 10 Gb / s is split, it won’t adequately provide three 4K displays, six USB ports each requiring up to 10 Gb / s, one Gigabit Ethernet port, and the other bandwidth-consuming items here.

At a rough estimate, the ports on this device would require more than 76 GB / s of connection to the host computer to have all the necessary bandwidth, and it only has 10 GB / s.

The obvious conclusion is that it’s not practical, or at least some important trade-offs are needed in what you can realistically connect and how it might work.

The way these limitations are handled by the SD4900P is twofold. And, depending on how you want to use this device, either one may work for you.

The first is that the docking station supports Alt USB-C mode, where it can transfer video data via USB-C merged with other data. The downside to this option is that each display you add eats out of the available bandwidth, and if you use all three screens, there won’t be much left for other uses.

(Image credit: Kensington Computer Products Group, a division of ACCO Brands)

The alternative display connection method is DisplayLink, another technology designed to perform multiple displays over limited bandwidth.

If you don’t have USB-C and use the USB-A to USB-C cable provided by Kensington, then a maximum of two 4K displays is possible.

DisplayLink must be installed on the host system which can compress data from a video display to send it to the port on the docking station, thereby reducing bandwidth requirements.

Our experience with DisplayLink has not been great, we admit it. Because it requires significant processing on the PC, the amount of bandwidth it uses can vary wildly depending on the amount of change that occurs, and most laptops don’t have the spare performance for pilot it correctly.

How it works for a specific user depends entirely on many factors, such as the laptop’s host hardware, monitor resolutions, and the amount of screen movement.

Those expecting smooth 4K video on three monitors from a computer with integrated GPU and USB-A connection will likely be disappointed. But those with less ambitious goals, USB-C and more concurrent PC hardware might be pleasantly surprised at what they can do.

(Image credit: Kensington Computer Products Group, a division of ACCO Brands)


The UK cost of the SD4900P is £ 279.02, and it can be purchased in the United States for $ 277.96 in online stores.

This makes it one of the most expensive options for a USB connected docking station.

If you’re ready to accept dual display output, there are many alternatives that offer better value for money and those with Thunderbolt 3 are less compromised in terms of bandwidth.

We highly recommend the Caldigit USB-C Pro docking station that we recently reviewed. As it is cheaper, sports a metallic exterior and is both USB-C and Thunderbolt 3 connectable.

Kensington’s SD5000T Thunderbolt 3 Dock costs a little more but delivers 85 watts of power to the connected laptop.

A much cheaper choice is the Dell D3100 Dock, which supports three displays (only one in 4K) over USB 3.0, but you can buy three for the price of an SD4900P.

(Image credit: Kensington Computer Products Group, a division of ACCO Brands)

Final verdict

On paper, this material looks wonderful, but the lack of Thunderbolt 3 and the 60-watt limit on passthrough charge power make reality less desirable.

Being able to wire three monitors is also a nice option, but you need a powerful laptop to drive this configuration smoothly and triple the display functions better on docks that use Thunderbolt 3 and not DisplayLink software.

If you want each docking station port to work as if it were on the laptop, you need to invest in a Thunderbolt 3 docking station that can give you the bandwidth to run screens and have peripherals at high speed at the same time ..

And the other warning to this material is the charge. The 60 watts provided are not enough to charge the most powerful Ultrabooks, such as the 15-inch Apple MacBook Pro.

Therefore, you should check the charging requirements of any laptop that this docking station is likely to be using. Or, if the laptop does not have USB-C, assume that charging is not something the docking station will provide.

Overall, the tradeoffs for getting triple displays are too great, and most users would be better off with a dual screen option and plugging the third screen directly into the laptop to reduce bandwidth overhead.

For many users, this dock would work well, but we think other designs offer better value for money and less caveats.

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