The main issue is, whenever I connect my D6000 dock to my laptop (Via USB-C and USB-3.0) and try to do anything on it, it appears extremely sluggish, and if I try to watch any media on it, it occasionally freezes/pauses the video only to resume a half-second afterwards. On the laptop screen, and the other monitor I currently have hoked into the laptop directly, this issue does not occur. All of the drivers have been installed/updated and the laptop is more than capable of running multiple external displays. It's crazy frustrating.
It's because the D6000 uses a DisplayLink chip to send display traffic rather than a native GPU output like most other docks, such as the E-Docks, WD15, and TB16. That's how it's able to drive up to 3x 4K @ 60 Hz displays and work over regular USB-A, which has no native support for video output, but DisplayLink has several drawbacks. DisplayLink works by using a driver on your system to have your CPU and GPU compress display data before transmitting it as regular USB traffic -- which again is how it can use USB-A for video output. The D6000 also uses this mechanism even when connected via USB-C, even though some USB-C ports DO have native video output capabilities. But this compression has some side effects:
- If your CPU and/or GPU are already heavily utilized, they might bog down trying to compress that display data quickly enough.
- If your USB bus is already heavily utilized (e.g. a large file transfer to/from an external drive), then there might not be enough bandwidth to get data to the displays quickly enough.
- If large portions of the display are changing simultaneously, such as when watching full screen video or playing games, thereby increasing the NEED for extra compression and the bandwidth demands, then you're more likely to see issues there even if your CPU, GPU, and USB bus were fairly underutilized beforehand.
- Lastly, for systems with discrete GPUs that operate as render-only devices (which is how most systems are wired these days), a Windows limitation means that the discrete GPU cannot be used to accelerate content on any DisplayLink display.
If you don't need USB-A compatibility, you would be better served using the WD15 or TB16 docks. The main difference between those two is that the latter gets quadruple the display bandwidth, so it can support dual 4K and even some triple-display configurations, whereas the former can only do dual 1080p, but the latter requires your system to support Thunderbolt 3 rather than just USB-C with video output capability.
I just realized you never mentioned what system you're using, so I don't even know if the WD15 or TB16 are viable options for you since they require USB-C and Thunderbolt 3, respectively. If your system doesn't have either of those, then if it has an underside E-Dock connector, that would probably be your best bet. If it doesn't have that either, then if it has a DisplayPort output, you can buy an MST hub to run multiple displays off of that single output, including DVI/HDMI/VGA displays through the use of ACTIVE adapters attached to the hub if needed, and those displays would be driven natively by the GPU. Or if both of your displays supported DisplayPort and at least one of them had a DisplayPort output to support daisy-chaining, you could even skip the MST hub and just daisy-chain your displays together instead. If your system doesn't have DisplayPort either and only has one external display connector (probably HDMI?), then unfortunately DisplayLink is your only option for running multiple independent external displays.