Throw away everything snootch posted. He's wrong. I've been a member of JEDEC for years, 24 year electronics engineer, ETN, blah, blah, blah...
1st.
@EarthDog yes*
*in theory, but really no.
I'm going to explain this, but I got to start baby steps first so bare with me.
JEDEC. What is it?
It's an industry wide standard set so that any RAM (of the same generation) can run on any motherboard, with any CPU, whether that be Ryzen, Ryzen+, Ryzen 2, or Skylake, or whatever. Example: you buy a random stick of RAM, you put it into your new motherboard and CPU that just came out of the box, turn it on and it POSTS. It might not be at the speed and timings that are advertised on your box, because if it is faster than JEDEC spec, then it is considered overclocking.
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Example JEDEC DDR4, these are always the same and 1.2v, and that's the point of JEDEC:
Buy Crucial 4GB DDR4 2133 (PC4 17000) Desktop Memory Model CT4G4DFS8213 with fast shipping and top-rated customer service. Once you know, you Newegg!
www.newegg.com
Buy Crucial 4GB DDR4 2400 MT/s (PC4-19200) SR x8 DIMM 288-Pin - CT4G4DFS824A with fast shipping and top-rated customer service. Once you know, you Newegg!
www.newegg.com
Buy Crucial 4GB Single DDR4 2666 MT/s (PC4-21300) CL19 x8 UDIMM 288-Pin Memory - CT4G4DFS8266 with fast shipping and top-rated customer service. Once you know, you Newegg!
www.newegg.com
Buy Crucial 4GB 288-Pin DDR4 SDRAM DDR4 3200 (PC4 25600) Desktop Memory Model CT4G4DFS632A with fast shipping and top-rated customer service. Newegg shopping upgraded ™
www.newegg.com
Example: You bought some Neo 3600MT/s because it has shiny lights even though you have no idea how RAM really works. You put it in your motherboard and it posts at one of the JEDEC speeds programmed into the SPD table on the RAM, probably 2133MT/s CL15. You get pissed, so you post here, and here we are. Now if you enter your BIOS and set frequency to 3200MT/s and leave everything on AUTO (not X.M.P.), it should POST with the DDR4-3200 JEDEC frequency and timings, CL20...but at least it will work. It's guaranteed to work if your RAM and CPU are rated that high because it's an industry standard.
Now what about X.M.P.?
That is an Intel standard, period. It's spec'd by Intel in cooperation with the memory manufacturer to work on Intel memory controllers.
Intel® XMP allows you to overclock DDR3/DDR4 RAM memory with unlocked Intel® processors to perform beyond standard for the best gaming performance.
www.intel.com
Yes
@EarthDog here is a processor QVL
Can it work on AMD. Yes, sometimes it can, but it is not guaranteed because the timings are often too aggressive for AMD memory controller without additional tuning.
Some memory manufacturers will advertise "AMD ready", and what that means is they loosened some secondary timings in the X.M.P. profile so it's more likely to work, but still not guaranteed without some manual tuning.
In the past, AMD tried to come up with an equivalent standard for AMD processors called A.M.P. but that never really caught on with vendors. Hopefully if AMD gets the resources, we will see A.M.P. again with an AMD QVL.
But, but, but my QVL???
You read it on a QVL, so you still think it's just going to work out of the box right?
First of all, there's technically actually 3 QVL's: one for the processor, once for the motherboard, and one for the RAM.
Example: Ryzen 2 is guaranteed to work with RAM speed up to JEDEC 3200MT/s per AMD specification. Any faster than that is not guaranteed and is considered overclocking.
AMD RYZEN SPEC SHEET See they only cover JEDEC speeds, but of course you can overclock to go faster out of spec.
INTEL X.M.P. QVL See how detailed it is with specifics like BIOS version ect, but still does not tell you what voltages were used on the memory controller itself.
Your motherboard manufacturer has a QVL, but they don't tell you exactly what settings they used. They could have checked the RAM at JEDEC speeds, or X.M.P. or manually tuned. They don't specify what voltages they used. They could have had a silicon lottery memory controller, or maybe not. Maybe they pushed 1.4v through the memory controller and 1.5v through the DIMM, maybe they didn't. Every board manufacturer has a different method of validation, so if you are only looking at your motherboard QVL then you are a fool. Go ahead, email support from each company and see how many totally different answers you get. You won't get anything in writing except some generic marketing talk, and that's because they don't want to get sued.
ALSO THEY DON'T TELL YOU WHAT BIOS THEY USED FOR THE TEST.
Example of an X570 QVL and that's one of the more detailed ones.
Your memory manufacturer also has a QVL. See motherboard QVL.
Example OMG they don't tell you anything useful at all in that one.
Still trusting those QVLs?
Ok now all of the above is true and not refutable. Call it the ten commandments of RAM or whatever you want. But that doesn't mean you can't tune your RAM for more performance. You just need to learn how. I would start by reading your motherboard manual and getting familiar with the terms in your BIOS. I would stay away from forums like Reddit and Github and stick with reading guides from veteran overclockers like 1USMUS. His Ryzen memory software is pretty nice too and will get you in the ballpark of what your platform is capable.
Edited for spelling, swearing, and added some more links including CPU QVL for
@EarthDog
