This means the advice for a desktop system with 2 memory sticks of 8-16 GB each isn't quite correct.
The more memory sticks you add, the harder it is for the memory controller(s) inside the processor to read the signals and correct errors that can happen at such high speeds. The higher the frequencies, the faster the signals go through traces on the motherboard into the cpu and the harder it is for the processor to correctly decode those signals.
With two memory sticks (typical configurations most people have at home), it's easier to push data around, with 4 memory sticks it's a bit more difficult. The quality of the motherboard (and how the traces between cpu socket and memory slots are layed out) matters a lot as well.
Officially, threadripper supports up to 2933 Mhz on motherboards that have only 4 memory slots... you'll have difficulty finding a threadripper board with only 4 memory slots (1 stick per channel), most motherboards have 8 slots. The simple presence of 4 empty slots can affect the signals enough to make AMD not guarantee that the CPU can work with memory at 2933 Mhz.
With 4 sticks installed and 4 slots unused,the maximum guarantee is 2666 Mhz, anything else is "depends on motherboard quality and memory stick and timings you choose and voltage you use"
Even 3200 Mhz is more than what I would expect to work on Threadripper, and honestly anything more than 2933 Mhz brings so little performance increase that it may not be worth the hassle.
i meant memory voltage ... standard voltage is 1.2v , but most sticks are set on 1.35v when going over 2666 mhz. You can go a bit higher, but I wouldn't go above 1.4v... you shouldn't even have to go above 1.375v
You don't want any errors to show up there. Imagine you're downloading a file from the internet, an installer for an application, and one byte gets corrupted in ram as the file is downloaded. You launch the installer, install the software, run the software and then randomly the application crashes because of that byte inside the executable that got corrupted.
You could spend hours to days investigating why the software crashes, blaming your processor, your video card, other things, when the problem was a memory error at some point.