There's threads on here discussing the Ryzen 5000 series memory configurations.

They run at an infinity fabric frequency of 1733 Mhz. This means memory runs at 3466 Mhz, slightly above the rated 3400 Mhz.

One person reported this caused windows hardware issues, and he had to send his machine back. I believe he is still waiting on a replacement.

Another person did not have hardware errors, but noticed their memory timings were slower than the 3400 Mhz XPM profile. I believe his timings were 22-20-20 instead of 20-20-20.

Based on the information on this board, the solution is to use the 3400 Mhz and run at looser memory timings. Now I don't know if that is automatically done by the latest bios, or if that is manually set in the bios. It's not a good solution because 20-20-20 is already slow, 22-20-20 is worse. 

Do your research, because I am pretty sure this config needs 3600 Mhz memory to function properly. However, that is not validated and Dell does not sell 3600 Mhz memory as far as I am aware off.

The information and details are in the threads. Here is the main thread: https://www.dell.com/community/Alienware-Desktops/Aurora-R10-5950X-random-power-off-restarts/td-p/7829031

The CPU can only communicate at one frequency with all RAM modules. It will downclock to the lowest common frequency. It will work, but no idea what frequency will be common, this may be less than 3200Mhz.

There are 2 profiles in XMP, again only 1 can be used, if the other pair is not on the same XMP profile, one of the pairs will run JEDEC specs.

The 4x16GB kit means replacing the 2x?? existing memory.

Just remember, if you are adding one dual channel kit to another dual channel kit, as long the kits are compatible, the 2 kits do not need to have the same timings nor the same size.

I have seen others recommend HyperX and Crucial for most rigs, there should be many threads here on the subject for R10.

Also be aware these systems are very finicky when it comes to memory support, and Dell only validates against a handful of solutions. (And only HyperX, but OEM HyperX not retail HyperX).

Basically, on paper it should work, practically it likely will not work. Mostly because Dell does not validate 3466 Mhz memory kits. Just be sure you can send them back for a full refund should they not work, and ensure to test them properly with memtest86 or a similar program to ensure they work without errors.

Good point, there are some issues with 3466Mhz, it is over spec validated 3400Mhz. 

Here is a success story on 3200Mhz retail.