Can't speak for anyone else, but I frequently upgrade people's PCs with kits of additional ram(2+2=4), frequently using Corsair. Never have or had any problems.
Well, you can speak for me in this regard. Not just for client/customer PCs, but family, friends, and my own PCs as well.
What you are talking about is what makes the PC space great. Choice.

Nothing in my reply, that you quoted, had anything to do with "choice". My entire reply, in fact, this whole line of the debate with you is about your FALSE claim that buying from different supplies "
almost guarantees problems". That simply is not true. You even obfuscated and negated your own argument by then claiming that Corsair buys from "
every single RAM supplier".
If one were to believe your first false claim, that would mean, according to your second false claim, that Corsair RAM is not even compatible with itself!

Or at least guaranteed to cause problems.

What you are talking about is what makes the PC space great. Choice. So yes any SSD you buy will work on an X86 machine. So in turn any RAM kit should work with any modern MB. There is one distinction though. QVL is not something that the end user creates but the MB vendor.
Please don't try to explain what I am talking about - you are not good at it.
As noted above, I was not talking about "choice".
This discussion has absolutely nothing to with SSDs. But to that, you are wrong to claim any SSD will work on an x86 machine. That's another blanket statement that is clearly wrong.
And IN NO WAY can one conclude that "
in turn" any RAM kit should work with any modern MB. Even with the clarifier "should", that is wrong.
As for the QVL, there is an assumption here that the motherboard, chipset and CPU supports RAM intended to be used in that specific board - regardless if listed on the QVL or not. I assumed that assumption was understood. Perhaps I was wrong for assuming, again.
Folks need to realize that it is impossible for motherboard makers to test and verify every stick made by every RAM maker out there for every board they ever make. There just are too many. So users do NOT have to buy listed RAM but should buy RAM with
the same specs as listed RAM to ensure compatibility. Even then, newer, faster (or bigger) RAM that comes out AFTER the board leaves the factory and production winds down may not be listed under any brand, but still be compatible. This happens because board makers don't spend (or don't have to spend) the resources to go back and update every QVL out there - especially when there will be no returns on that investment.
The fact that you're arguing a point that is not only incorrect & flawed but also not the focus of what the OP asked about.
Right. For example,
Are you telling me that no one complained about Corsair RAM on AM4? Is not the prevailing recommendation that you use 2 sticks in a build?
Again, no one said problems "never" happen. They,
on occasion do. But again, those are anecdotal exceptions, not the norm.
If you did your homework, you would see reports of similar issues with Crucial, G.Skill, Kingston and [fill-in-the-blank] too. And you would find reports of problems with those same makers and AM3, AM5, and likely every Intel socket that ever existed too.
"Prevailing" recommendation (as in more often than not?) in builds? No! At least not for the reasons you are suggesting.
Two sticks in a "build" are commonly recommended for the following reasons:
- You need 2 sticks to enable dual channel. So, for example, 2 x 8GB is often recommended over 1 x 16GB.
- 2 sticks are easier to install than 4.
- 2 sticks cost less than 4.
- On a 4 slot board, using 2 sticks during the build leaves 2 slots available for easy, typically less expensive upgrades.
It is true, there are some scenarios where adding 2 more sticks decreases RAM speeds
a bit and therefore may impact some apps, particularly some games. HOWEVER, for most users and most games, any impact is negligible, if noticeable at all - except in their benchmark scores and placebo-effect driven perceptions.
But it is also true that adding more RAM, even if RAM speeds decrease, generally improves overall performance of the operating system as well as the performance of many other apps - like graphics editing, compiling data and more.
This last point is important because, despite what many "PC" gamers seem to believe (in part, due to marketing hype

) the computer world does not revolve around gamers as more PC users use their PCs for other uses, besides gaming. There are billions of gamers, but, by far, the majority game on consoles, not PCs.