The HyperX has heat spreaders and are thus more popular with gamers.  It looks better too.

I think the HyperX DDR4-2666 will work with your XPS8930. 

Do you know the Dell P/N of the existing 16 GB sticks in your system?  If it is TP9W1, which name brand?

https://www.dell.com/community/XPS-Desktops/XPS-8930-memory-upgrade-from-16GB-to-64GB/td-p/5840940/page/2

Dell validated OEM memory sticks =
TP9W1 16GB, DDR4, 2666MHz, 2RX8, 8G, 1Gx72, 8K, 288Pin, Dual Rank, Unbuffered, 1.2v, Non-ECC
Hynix HMA82GU6CJR8N-VK
Micron MTA16ATF2G64AZ-2G6E1
Micron MTA16ATF2G64AZ-2G6H1
Samsung M378A2K43CB1-CTD

Y7N41 8GB, DDR4, 2666MHz, 1RX8, 8G, 1Gx64, 8K, 288Pin, Single Rank, Unbuffered, 1.2v, Non-ECC
Hynix HMA81GU6CJR8N-VK
Micron MTA8ATF1G64AZ-2G6E1
Micron MTA8ATF1G64AZ-2G6H1
Samsung M378A1K43CB2-CTD

FDFMV 4GB, DDR4, 2400MHz, 512x8, 288Pin, Single Rank, Unbuffered, 1.2v, Non-ECC
Smart SF464128CK8I6GKSEG

A couple of questions:

1. What is your current memory configuration? One 16GB memory module or two 8GB memory modules.

2. What processor do you have? i3 processor comes with 2400 MHz memory and I5, i7, and i7k processor come with 2666 MHz memory.

I cannot tell from the spec whether or not the HyperX Fury memory will work at 2666 MHz. XPS 8930 memory speed is set by reading the SPD (Serial Presence Detect) speed and that is not specified on the datasheet. The XPS 8930 is not capable of using the XMP (Extreme Memory Profile). The Kingston spec mentions the SPD is programmed to the JEDEC standard latency DDR4-2666 timing so hopefully that also applies to the speed.

To find out more about the memory module(s) in your system you could run a program like CPU-Z.