X370 SLI Killer - System doesnt see one ram stick

You're in one of Ryzens Mhz holes at 3000. That's why the BIOS automatically downclocks it to 2933. It states as much in the manual and on this MB's product pages.

This DOES NOT explain your system only seeing 1 stick and in your last post you seem to be ignoring this. Again, with experience, if one single slot is acting up regardless of what stick you put in it that usually signifies a bent pin(s). It happens to the best of us. I'm known on rare occasion to still do it. It happens, and is easy to do.

You need to pull the processor. As I said it may be a pin issue, or, and this is just as believable, and much cheaper, the processor just needs re-seated.

But either on of those two is more believable that a defective mem slot.

ok thank you...

Now regarding if i will be able to run my memory on its full potential (2933 MHz), my question:

The memory controller (IMC) is located on the CPU die these days so yes, a bent pin can prevent slots from working or cause dual channel not to work etc. I have seen it numerous times, this isn't a guess, its a fact.

But most memory modules, WILL work in future, just needing a bios update... There is nothing hardware wise or anything else, that is not fixable with bios (or other "software") updates... Correct?

Or is there a possibility that even countless updates in the future there will be a lot RAMs that wont work at ryzen (or wont work with ryzen on their native (higher) frequencies...?)

I have been told that bios updates should solve 95% of the issues... i just need to wait... correct?

First, your Corsair memory, which as we can see on the Amazon page you posted, is designed for Intel X99 and 100 series chipset boards. That information is from Corsair.

Corsair would like us to believe that all of their DDR4 memory models are compatible with Ryzen systems, but as we know now, it's not that simple, or true.

The XMP profiles in your memory, designed for the memory controllers in Intel processors, don't work with the Ryzen memory controller. The Ryzen memory controller is different than Intel's. For example, Ryzen does not support a memory speed of 3000 and 3400. DDR4 3000 memory must be set manually to 2933.

Ryzen's memory controller, at any speed above 2133, needs a Command Rate (CR) of 1. I have used DDR4 memory with my X99, Z170, H110, and Z270 Intel systems, and all of the XMP profiles or default JEDEC SPD data has the CR set to 2.

Your board has the single locking latch style memory slots, which are more tricky to get the memory fully seated in the slot. The only way we could know if the memory was seated correctly is if we could see the board ourselves. So impossible for us to know if the A1 slot is bad, I would say it is not bad.

The default speed of your DDR4 memory is 2133, so it is normal for it to run at that speed until you set it to its higher speed. But as I said, you cannot use the XMP profile to do that, since it won't have the correct settings for a Ryzen system.

You plan on buying another set of that memory in two or more years? That means using two sets of unmatched memory together. Good luck with that, there are reasons why memory is sold in matched sets. Don't be surprised if they don't work together. Also, the greater the amount of memory being used, the more difficult it is to have it running at a higher speed. Check any board's memory support list for examples of that.

The Ryzen platform is still very new, and updates from AMD for memory compatibility are still being provided by AMD. Memory compatibility is the biggest issue Ryzen has now, and even DDR4 memory that was designed for Ryzen do not work perfectly yet.