There are a few posts on this site called “The Grand(ish) Experiment” where I talk about using Dell Venue tablets with their respective docking stations, exploring their potential to replace desktop machines. The idea was that every office desk and classroom would have a docking station, teachers would have their own tablets with the software and files that they needed and that they would be able to use any classroom in the building and not have to book a specific one. It didn’t really pan out; the docks were temperamental, the tablets were either underpowered or too big and heavy, the optional hardware keyboards had issues and the current OS at the time was Windows 8. People didn’t like the hardware that we were trying so there wasn’t really the interest to keep the experiment going and it all got forgotten about, as, sadly, did the article series.
A few years and two jobs later, I’m looking at something similar again, albeit under very different circumstances. I now work in the Central Services department for a Multi Academy Trust of schools. The organisation has nine different sites and while I spend most of my time at one particular one, I do spend at least one day a week at two of the other eight and have to visit the other six periodically. The situation is the same for a lot of my colleagues in Central Services, not just the IT people.
The computers in our main office are pretty old. The most modern one is an HP Compaq machine with a second generation Core i5 CPU, 4GB of RAM and a standard magnetic hard drive so it’s safe to say that the hardware is due to be updated. A large proportion of the staff in our Central Services department are like me in that they have to attend the other sites as well so the majority of them also have laptops, again which are pretty old and are due for replacement.
Bearing that in mind, to replace all of the desktops and issue these people with new laptops which get used but not very heavily seemed like a pretty major waste of money. It seemed to be a much better idea to issue everyone with a new laptop and put a docking station on everyone’s desk. That way, everyone still gets a new, faster machine but the offices become a lot more flexible because wherever the person ends up sitting, they get the resources that they need. We’ve recently standardised on Dell hardware, in particular the Dell Latitude 7390 laptop for our Central staff. With a fast SSD, a reasonable amount of RAM and a quad core CPU, there is no reason why these laptops couldn’t function as desktop replacements. Issuing a laptop to everyone would also end the, um, disputes between the people in our Finance department and the people in our other departments as only a couple of the computers in our satellite offices have the Finance software installed. The idea is that if people have a laptop with the software they need already installed, they can hook up to a docking station anywhere and do what they need. Failing that, even just find a desk somewhere and do their work, even if they can’t dock.
With that in mind, I approached our account manager at Dell and asked her what she would suggest for us. The laptops that we’re using don’t have old fashioned docking ports on the bottom of them so we had to look at their USB docks. Dell suggested three:
First of all, the D3100. This dock is based around a Displaylink chipset. Because of this, everything on it (video, network, audio) is driven using the USB 3.0 bus on your machine. It can drive up to three displays, one of which can be 4K. It connects to your computer with a USB 3.0 A plug. It won’t charge your laptop.
Next up, the WD15. This is a USB 3.1 Gen 2 dock which can drive up to two screens up to 1080P. It also has an Ethernet and audio ports and you can charge your laptop with it, making it a one cable solution. Unlike the D3100, this dock acts as a DisplayPort MST hub so the displays that it drives are driven from your laptops own GPU or APU, rather than from a chip connected to your USB port. This should improve video performance, especially if your laptop has a discrete GPU. It is available with two sizes of power adapter (120W and 180W), the bigger of which is required if you have one of Dell’s larger laptops and want to charge it from the dock.
Lastly, the WD16. This is a Thunderbolt 3 dock, again connected by USB C connector. Again, it functions as a DisplayPort MST Hub but unlike the WD15, it can drive up to three displays at 2560×1600 at 60Hz, up to two 4K displays at 60Hz or one 5K display at 60Hz. It also has another Thunderbolt 3 port as a pass through and the usual Ethernet, audio and additional USB ports. This dock also can come with one of two power adapters (180W and 240W) and again, the bigger PSU is required if you have one of Dell’s larger laptops and want to charge it from the dock.
I have used two of these docks, the D3100 and the WD16. I’ve not used the WD15 so I will say up front that anything I say about it here is conjecture based on its spec and appearance.
So first of all, the D3100. As I say, it’s based around a DisplayLink chipset. It has a full sized DisplayPort for your 4K display, two HDMI ports, two USB 2.0 ports on the back and three USB 3.0 ports on the front. Along with that, there is a headphone port on the front and a Line-Out port on the back. The dock is nicely laid out with everything in the place you’d expect it to be. Along with that, it features a PXE boot ROM so you can built workstations from it (Rarer than you’d think on a USB networking device) and it supports WOL.
All of the the ports are run from your USB 3.0 port, including the displays. That means that the Ethernet port, any other USB peripherals that you connect to it and in theory, a 4K display and a pair of 1080P displays and therefore 12.5 million pixels being refreshed 60 times a second, all have to share that 5Gbps of bandwidth that the port provides. Considering that an uncompressed 4K stream at 60Hz would use almost 9Gbps of bandwidth, I was sceptical that this was going to work very well and, well, so it turned out.
At the time, I was running a mid 2014 MacBook Pro with Windows 10 and a Core i5 4278U CPU. When I first started using it, I was using a pair of 20″ monitors running with a 1600×900 resolution. With these monitors, it worked well. However, the size and resolution of those two monitors was too low for me and I asked for some bigger monitors. I put on a pair of 1080P monitors and that’s when I started having performance issues. As soon as I started using those monitors, the displays started glitching, the refresh rates were variable and using it was just annoying. CPU usage was all over the place with no obvious culprit. The Mac that I was using at the time had a lot of external ports (Two Thunderbolt 2 ports and an HDMI port) so I connected the monitors directly to the laptop to see if the performance issues would go away. They did so that was how I used the laptop until it came time to replace it.
I don’t know if the laptop I was using was underpowered for the compression tricks that DisplayLink must have to use to drive more than 4 million pixels over 5Gbps, if I had a bad dock or if there is an inherent problem with the DisplayLink chipset. As I say, it worked fine with two lower resolution monitors so I expect that the Mac was too old to run this properly. I can quite happily recommend the dock from that perspective, i.e. if your running a single monitor or two lower resolution displays from it on reasonably modern hardware, but for our purposes we decided that it was inadequate.
WD15 and TB16
So, instead, the two USB C docks running as DisplayPort MST hubs. When I originally looked at the spec of these devices, I thought it was pretty cut and dried. The TB16 wasn’t significantly more expensive. It’s Thunderbolt so it’s likely to be a faster performer. So we ordered some. This is what we found.
First of all, considering what this thing is, it’s bloody huge! It’s only half an inch smaller on the width and length than the original Mac Mini and significantly larger than an Intel NUC. The Thunderbolt cable is about half a metre long and is built into the docking station.
It has four monitor outputs: A full-sized DisplayPort, a Mini DisplayPort, an HDMI port and a VGA port. It has a pair of USB 2 ports, a USB 3 Type A port, a Thunderbolt 3/USB C port, a Gigabit Ethernet port, an audio line-out port and the power input on the back of the device and two further USB 3 Type A ports and a combo headphone/microphone socket on the front. The aforementioned captive Thunderbolt cable is on the left hand side of the device when you’re looking at it from the front.
This is where things start to go a little bit wrong for this thing. The port layout is fine and generous but all of the Dell laptops that I’ve seen (various XPSes, Latitudes and a Precision) have their Thunderbolt 3 ports on the left hand side of the device as well. This, along with the relative shortness of the docking cable and the size of the USB plug into the laptop (about 1.5″!), makes positioning the dock very awkward. Ideally, with a docking station, you want it stuffed out of the way somewhere at the back of your desk but the length of the cable and its position on the left makes that difficult to achieve. I tried various positions to find what worked best. Most people seem to prefer putting the dock on the left hand side of their desk with the front ports facing forward (funny that!) and having the Thunderbolt cable loop round. The problem that I found with that was that the laptop has to be within 25cm of the dock because the bend radius of the Thunderbolt cable is quite large and that makes the solution take up a lot of space on the desk and makes it hard to access the ports of the front of the dock. The second position that I tried was to put my laptop in the middle of my desk, underneath my monitors, put the dock on the left side of my desk and have the left side of the dock point right towards the laptop. I didn’t like this solution very much either as it meant that the back ports were facing the front which was messy. I did try turning the dock upside-down so that the front ports were on the front but this just made the dock slide all over the desk and it meant I couldn’t get at the power button on the top of the dock.
Eventually, I found the best way that I could set up the dock for me was to rest the dock on top of one of my speakers with the Thunderbolt cable pointing down like a tail. The ports on the back point to the left, the ports on the front point right and I can position the dock where it’s reasonably accessible. It’s nowhere near ideal but I found it was the best way for me.
Awkward cable positioning aside, how good is this thing otherwise? Well, lets see. The thing I found most disappointing about this dock is that the audio and Ethernet ports are USB devices. Considering that Thunderbolt is essentially an extension of a computer’s PCI Express bus, it seems a bit, well, cheap to saddle this thing with a USB NIC. A PCI Express one would be better as it would take up less system resources and it would able to share up to 40Gbps of bandwidth with the host system, rather than the 5 or 10Gbps that shoving it on the USB bus restricts it to. Yes, that 5 or 10Gbps for the Ethernet port by itself is fine but as the D3100 proves, contention starts to become an issue as you add more USB peripherals to a system.
Moaning about that aside, when you first open the box for one of these docks, there is a big piece of paper that tells you in no uncertain terms to make sure that you go to the Dell website and download the latest drivers and firmware that are available for this dock and, if you’re using a Dell laptop, to make sure that you’re using the latest BIOS for it.
Do NOT ignore any of these instructions
All of the docks that we received from Dell had a pretty old firmware on them and when using the docks with the OOB firmware, they were a nightmare. They constantly disconnected from their host and when they were connected, they were (somehow) laggy and made the laptop CPU usage spike. Updating the firmware on the dock and the laptop resolved these issues immediately. With that installed, the laptop behaved exactly how you would expect it to. Docking and undocking is simple. You don’t have to jump through any hoops in Windows, just pull the cable out and continue working. When you go back to your desk, you put the cable back in and away you go. All of the laptops that I’ve tried with these docks (Dell Latitude 7380 and 7390, Dell XPS 13 and 15, Dell Precision 5530) work perfectly and support USB charging.
I’ve managed to PXE boot and build laptops with these docks attached and this includes laptops which don’t have built-in Ethernet ports. With the latest firmwares, they do exactly what they’re supposed to do and that in itself is high praise.
So now we come back to the WD15. As I say, I’ve not used the WD15 dock so this is conjecture. However, I’m going to assume that it works as well as the TB16 does. In that case, considering that internally, the WD15 and TB16 both have very similar hardware, I’m actually struggling to justify the extra expense for the TB16. They both have the same audio and Ethernet connectivity, both driven from the machine’s USB 3.1 bus. They both act as DisplayPort MST hubs so the extra monitors are driven from the laptop’s GPU. The only advantage that the TB16 gives you is that you can drive more monitors from it and those that you can drive can also have higher resolutions. That’s great but in a general office environment, it isn’t actually that big of an advantage. Very few people in our organisation has a monitor with a resolution higher than 1080p and no-one has more than two monitors so most people get precisely zero benefit if they use a TB16 instead of a WD15. If anything, the WD15 might be the better choice under some circumstances because it has a longer connection cable, albeit still a daft captive one on the left side of the dock. So I guess I’m saying, unless you see a need to drive more than two monitors or monitors with higher resolutions than 1080P, don’t bother with the Thunderbolt dock and get the USB one instead. I think in future, that’s what I’m going to suggest.
It’s still too early to draw any conclusions but the feedback I’ve been getting from staff about the laptop/docking stations has so far been positive. They’re happy that they can just rock up to a desk and be using their own machines. I’m also using a laptop and dock and I couldn’t be happier with the arrangement. I’ll try to revisit this article in another three or four months and see if there’s anything interesting to say.