XPS 13 9365: Is it supposed to support Gigabit download speeds?

@J_Travis  One other thing: Yes, GbE means Gigabit Ethernet, and considering that the next step down would be only 100 Mbps, if you’re able to get 400 Mbps, then you have a Gigabit link from the Ethernet controller in your docking station all the way out to your cable modem. So the bottleneck will either be your Internet connection, the connection between the docking station and your laptop, or possibly processing overhead on your router that’s introducing a bottleneck, but that seems very unlikely given your equipment, since to my knowledge Linksys routers don’t support really advanced packet processing that would create that sort of overhead.

Do you have any other device in your home with a Gigabit Ethernet adapter? It would be helpful if you could test another device, or better yet the network speed between two devices on your local network in order to start isolating variables. Using a single laptop running through an Ethernet interface on an external device and measuring Internet speed rather than being able to measure network speed introduces quite a few confounding variables.

@J_Travis  The culprit might be that USB-C extension cable. It might be creating a total cable length that causes the USB-C connection to be unable to maintain USB 3.x speeds and therefore fall back to USB 2.0, or the extension cable itself might specifically only support USB 2.0 and power because it might not have the additional wiring and pins to support USB 3.x. The maximum theoretical speed of USB 2.0 is 480 Mbps, so that might explain the 400 result you’re getting. What happens if you don’t use the extension cable?

And FYI in this case the problem wouldn’t be the system. If you’re using an external network adapter, then the capabilities of the adapter and how you’ve got it connected to the system would be the only relevant factors. The XPS 13 has no built-in Ethernet controller, so the question of whether it supports Gigabit Ethernet doesn’t actually make sense. The Ethernet controller is in your “mini-dock“ adapter.

@jphughan Thanks for your quick reply and your great feedback. Your points make total sense to me, especially the one about the XPS 13 having no internal  Ethernet controller and the one I'm seeing in "view network connections" being the one inside my Totu docking station (slap-my-forehead duh!).

Given your input, I'm beginning to think my new Comcast buddy was right - my XPS 13 9365 is only capable of download speeds south of 500 Mbps. The primary reason I'm drawing that conclusion is in direct response to your point about the extension cable (which by the way - according to the manufacturer - is rated at 10Gbps). Because I was initially worried about all the stuff in between the modem and my machine (including the Totu box), I purchased the Uni USB-C Ethernet adapter and connected it directly from my XPS to the Arris modem via Cat 6 (not Cat 5e) cable. The speed tests from three different sources using that "semi-direct" connection all returned less than 500 Mbps.

Methinks I'm stuck with getting half the download speed I'm paying for until I upgrade my machine. Fortunately I AM usually receiving the full upload speed (35+ Mbps) which is what I was really after.

@J_Travis  Your XPS 13 would easily handle download speeds far greater than 500 Mbps.  Laptops that are 15 years old could handle Gigabit speeds, and modern systems wouldn't even bottleneck a 10 Gbps network connection if you had the hardware for it.  But it might be wherever you're speed testing, since 1 Gbps is much faster than most people's Internet connections, so it's possible that a single source just isn't saturating your link.  If you haven't already, try Fast.com, which is run by Netflix . They have a dead simple speed test (download only), and if anybody has bandwidth to spare, it will be Netflix.  But here again it would be nice if you had a way to perform a speed test within your own network.

Good to hear the extension cable is rated properly, but fyi those can be problematic.  First of all, you can't string an unlimited number of extension cables together and expect the end result to perform up to the specs that each cable in the chain is rated for, in case you didn't realize that.  But even apart from that, the transition between a male plug and a female connector that a signal has to cross when you use an extension cable is actually a significant source of signal loss, so sometimes a cable run that's made up of one or more extension cables can perform worse than a single cable of the same total length would have.  In this case I'm guessing that maybe your docking station has a permanently attached short cable, so an extension cable was your only option rather than just going with a longer cable, but just fyi.  In any case, if you have issues like this, it's always a good idea to cut out the extension cable to see if it makes a difference, even if you're only using one and it's rated to be up to snuff.

@jphughan More excellent feedback. There's hope yet. I'll check out your tips! Thanks again

@J_Travis No the CPU cant handle it, I too have a 9365 and after returning a few other laptops, only 1 came close to gigabit which was a Microsoft surface around 800 ish.  Around 400 is what i get on my 9365 if you watch the CPU usage you see that is the choke point, since then I have downgraded my service to 300/300. 

@Thumbilina  It may depend on the type of data that’s coming in and/or where you’re writing it (memory vs. disk). Gigabit Ethernet has been around on laptops since at least 2003, and CPUs obviously weren’t as fast back then. But it is NOT the case that laptops have only recently gained the ability to fully utilize a Gigabit Ethernet connection. There are now 10-Gigabit Ethernet adapters available, after all.

Hi all, sorry to revive an old thread, but I have also been finding that my XPS 13 cannot reach 1000 Gb speeds, at least not regularly. I just got a 1G down link to my house. All other computers can get to 950-975 mbs regularly, and my Dell XPS 9380 laptop typically gets only 600-800 mbs down, after many tests. I tested with both a brand-new Dell Thunderbolt Dock WD19TBS hooked up via the supplied Thunderbolt cable, and latest Realtek Ethernet driver from Dell Support. I also tested speed using a standalone Best Buy Essentials USB-C to Ethernet Adapter (BE-PA3C6E-C). The latter actually performed better each time. Looks like according to my oola Speedtest Windows app/widget, my average speed is 798 mbs. 

I will qualify this by saying that, just this morning, I did a test with the Best Buy adaptor, and I actually hit 927 mbs a single time, but I cannot replicate this. All 24 of my other tests were between 666 mbs and 824 mbs. It appears that best-buy also uses the same Realtek adaptor, so not sure why it is faster, perhaps because it is dedicated to ONLY doing ethernet as its function. Perhaps when a future RealTek driver comes out, both the dock and the standalone adaptor can reach 975 or 1000 mbs. Cross fingers!

I just tried again on mines via speedtest.net, fast.com testmy.net and max is about 300 thru a dell dock wd19 every test maxes out the cpu to 100%  and via the app hwinfo64 thermal throttling is also kicking in.  I hardly use my 9365 since it does not have a fan so anything multimedia around the internet it chokes on then thermal throttling kicks in.  I have an Fujitsu Stylistic ST5022 from 2005 ish that has gigabit ethernet when I fast.com it gets about 50.  When I use my HP Z600 workstation desktop with DUAL X5675 Xeons speedtest.net with 700 down cpu usage for it is about 30% testmy.net has a peak or 2 at 65% but about 30% for about 500 down and fast.com about 25% and about 700 down and IPAD M1 cpu same dell dock speedtest.net 700 down.  So looks like these websites are using RAM and not storage since the 9365 is NVME at around 1600 where as my z600 is just an SSD around 550.  The cpu is  a i7-7y75 it looks like the lenovo thinkpad x1 also had it and poking around the internet seems like people have slow gigabit ethernet also.  I use to have gigabit ethernet but downgraded to 500 but get 700 to my ISP test servers.