Latitude 7480 - WD15/K17A Docking Station: Setting up 3 monitors

*EDIT* - I found a simple work-around; You can run 2 displays from your port replicator, and the 3rd display from the laptop's HDMI port. If you do this, you should be able to use full resolution. I just figured this out, and I'm kinda pleased with myself.

I have a very similar setup, except i7-6600U 2.60GHz. Our port replicator won't do more than 2 monitors at full resolution. In fact, the dock you (and I) have won't support quad HD either. I've brought this dock home because of this limitation, and you'll have to use either [this|http://www.dell.com/en-us/shop/accessories/apd/452-bcnp?ref=p13n_std_pdp_mv&c=us&cs=19&l=en&s=dhs] or [this|http://www.dell.com/en-us/shop/accessories/apd/452-bcnu?ref=p13n_std_pdp_mv&c=us&cs=19&l=en&s=dhs] in order to get what you want. These beefier docks have built in graphics in order to deliver what you're looking for.

UPDATE: I went and checked the WD15's manual for you.  The screenshot below is from the last page, which contains the relevant information. Next time it might be better to purchase only enough equipment to validate your intended configuration(s) before committing to the entire order and discovering issues like this only after rolling everything out and affecting people's productivity -- and maybe even check the specs of the equipment you're considering before purchasing even the test samples. The aforementioned TB16 has a completely different set of possible display configurations.

The WD15 uses USB-C, which only provides the bandwidth of a single DP 1.2 output, and only half of that bandwidth is available when using a dock because the pins that would've carried the other half (e.g. if using a direct USB-C to HDMI adapter) are instead being used to support USB traffic for the dock's USB ports.  Half of a DP 1.2 output is not enough bandwidth to drive 3x 1080p displays; the WD15's product page, specs, and manual all indicate that it will only do dual 1080p.  It SHOULD be enough for 3x 1680x1050, and the Intel GPU does support three displays, but I'm not sure if the dock itself will support that configuration (UPDATE: See below.) You may want to read the manual for the WD15, available on support.dell.com if you choose to select your product and go to Accessories > Docks > WD15.

Another option would be to switch to the TB16 dock, which definitely does support 3 1080p displays, although it's more expensive and would also require that your 7480s have Thunderbolt 3, which is optional on that model.

JFSAT

Do you believe the D6000 Universal dock to be a good option as well? That is what our POC at Dell advised but that's not saying much.

jphughan,

It seems a far simpler solution to post here for assistance as opposed to parsing the sea of opinions we were finding elsewhere. I am not in charge of purchasing/requisitions and am feeling the frustration and impact to productivity myself, which is why I posted here. Unfortunately, I am but a lowly tech and am not consulted regarding specs in the purchasing of bundles from our vendor. I am certain the deciding factor was cost. I am currently using the WD15 with 3 Dell monitors, VGA/DP/HDMI, at 1600x900 (also listed in the manual for those cable types) with DPI adjusted to 100% to compensate for loss of real-estate as a temporary fix. The purchasing team has been advised by our point of contact that the D6000 dock would be optimal, though the TB16 has been cited here and in some other forums as well for thunderbolt models. I am looking for insight so that I might recommend the best product and avoid further issues for myself and my colleagues.

I appreciate your help

Have a great one.

My post wasn't intended to be condescending, just a suggestion for how to do things better next time. If it came across as condescending because it sounds obvious, then I apologize, but years of working in various IT roles has told me never to assume that an idea or piece of information is obvious, since things that have seemed blindingly, blatantly obvious to me have often been stunning revelations to others. Sorry if you read my post in a manner other than intended and are not in a position to improve the process that led to your current situation.

I also DO consider that a user may have exhausted other options, including having read documentation, before posting here, but given that the WD15's manual does in fact answer your question (and the product page only claims dual 1080p support), that seemed unlikely in this particular case.

Returning to more productive discussion, the D6000 uses a DisplayLink chip, which means that technically it can support extra displays (and at higher resolutions), but DisplayLink achieves this by not having the displays actually driven by the system's GPU. Instead, the system's CPU and GPU compress display data for transmission as standard USB data, and the DisplayLink chip in the dock then decompresses it before sending it to the displays. This allows displays to be attached over regular USB (rather than just USB-C, which actually does have a native GPU output wired to it), but the compression also means that when large portions of the display area change at once, such as when watching full screen video or gaming, the display can appear to bog down and/or show compression artifacts. It also drains battery life significantly more quickly, which admittedly isn't an issue with a dock setup, but DisplayLink products exist in other form factors.

So if you only need these displays for email and spreadsheets and the TB16 isn't an option, then it may be a good fit. Just realize that it works qualitatively differently from other docks.

You're welcome.  Note that I revised that last one a few times.  It turns out that it will charge laptops that only require 65W of power, which includes the 7480.  However, the WD15 and TB16 will charge laptops requiring up to 130W of power, such as the XPS 15 and some Precision models, just in case you have any of those in your environment.

I'll also add that other circumstances under which the limitations of DisplayLink can become apparent include a) periods of high USB activity from other devices (e.g. sustained transfers to/from an external hard drive), which forces display data to compete for USB bandwidth, and b) periods of high CPU utilization, which leaves less CPU capacity to compress the display data for transmission over USB.

jghughan,

Your subsequent replies have been most helpful.

Thank you for your time.

Fantastic!

I will ensure we swap the docks AND cables with the new models and the cables that come with it.

Your thoroughness is much appreciated.