Sometimes, it's easy to miss a step.  You don't delete apps.  Go over and disable all Killer's in services and startup (task manager).  Restart machine and check upload speed again.  XPS 8950 user managed to fix it here.
My one month old XPS 8950 upload speed is slow compared to my old Optiplex 7010. Both are connected to the same modem via Ethernet cable. My XPS 8950 download and upload speed are: 923.8 Mbps and 2.4 Mbps My old Optiplex 7010 download and upload speed are: 930.1 Mbps and 929.3 Mbps My internet provider is Telus and Telus has been checking for the last two days and found nothing wrong with them and suggest me to call Dell . I call Dell and Dell said the problem is  a software problem so I will have to pay Dell to solve the problem. Please give me advise. Should I pay Dell for the problem or should I return the one month old XPS 8950 to Costco because a defect desktop? Please not that I just have to reset the desktop because of the sound problem with the help of Dell Assist . Thank you for your input. Hop P
XPS 8950, upload speed via Ethernet cable slow