Ryzen users are having memory speed problems. (TL: DR it's your own fault).
I've been helping users on various forums for the last couple years since the Ryzen release. The number one help ticket item is RAM speeds.
Just because your motherboard has a QVL with your RAM kit on it, it doesn't mean your RAM is going to work at the advertised speed, automatically, right out of the box.
AMD Ryzen processors will run certain RAM speeds, but only guaranteed to boot automatically when the speeds are within the JEDEC thresholds. For 1st generation Ryzen, that's 2666MT/s (1333MHz), Ryzen+ is 2933MT/s, and Ryzen 2 is 3200MT/s, but at very loose JEDEC timings.
JEDEC DDR4
Example of Micron JEDEC DDR4-3200
Your fancy kits with the bling heat spreaders are binned and can work at better speed and timings than crummy JEDEC RAM, but only if you tune certain parameters. These include the various DIMM voltage settings and memory controller voltages in your BIOS. Typically you will need to raise DIMM voltage from 1.2v to 1.35v or sometimes as high as 1.5v for serious overclockers. Also since the SOC is the memory controller for AM4, you may need to raise SOC voltage. I've seen numerous theories on what is a safe SOC voltage floating around various forums, but AMD themselves raised SOC to 1.2v in their own overclocking guide just to get to 2933MT/s. I personally have to run about 1.21v to stabilize my own memory overclock.
AMD Official AM4 Tuning Guide
How can you get your fancy-out-of-spec-RAM to work fast? Well, you are going to have to set it up yourself. Luckily there are a few kits out there like FLAREX that have automatic profiles that usually work fine for AM4. Unfortunately most of the RAM on the market just has Intel X.M.P. timing charts that rarely work automatically on Ryzen because the memory controller just can't handle speeds like that without some manual help. This means you will most likely have to set ALL of your timings manually and adjust your voltages MANUALLY. This can be a real daunting task for most users to consider. Even for veteran overclockers, manually testing timings one at a time can be rather tedious. Luckily, there is a tool that can help eliminate much of the guesswork. A forum user by the name of 1usmus has been sampling various RAM kits, and has compiled a list of "SAFE" and "FAST" timings in a calculator. To make the calculator work, you'll need to figure out what memory ICs that your RAM kit uses. To do that, you can use Thaiphoon Burner.
Thaiphoon Burner
Ryzen DRAM Calculator
Ryzen Memory Guide by 1usmus
The DRAM calculator is an estimate, so if it doesn't work, try loosening timings and adding more voltage before blowing up the forums about your RAM blah, blah, blah (you'll just look like an idiot).
Read your motherboard manual and verify that you know how to manually CLEAR CMOS. This will be important to recover if you overbork your settings.
To measure the effectiveness of your memory overclock, I suggest the AIDA64 Extreme cache and memory benchmark. To test for stability I also suggest the AIDA64 Extreme stability tester. Unstable memory will corrupt your OS.
AIDA64 Extreme
And remember kids, READ YOUR MOTHERBOARD MANUAL.
I've been helping users on various forums for the last couple years since the Ryzen release. The number one help ticket item is RAM speeds.
Just because your motherboard has a QVL with your RAM kit on it, it doesn't mean your RAM is going to work at the advertised speed, automatically, right out of the box.
AMD Ryzen processors will run certain RAM speeds, but only guaranteed to boot automatically when the speeds are within the JEDEC thresholds. For 1st generation Ryzen, that's 2666MT/s (1333MHz), Ryzen+ is 2933MT/s, and Ryzen 2 is 3200MT/s, but at very loose JEDEC timings.
JEDEC DDR4
Example of Micron JEDEC DDR4-3200
Your fancy kits with the bling heat spreaders are binned and can work at better speed and timings than crummy JEDEC RAM, but only if you tune certain parameters. These include the various DIMM voltage settings and memory controller voltages in your BIOS. Typically you will need to raise DIMM voltage from 1.2v to 1.35v or sometimes as high as 1.5v for serious overclockers. Also since the SOC is the memory controller for AM4, you may need to raise SOC voltage. I've seen numerous theories on what is a safe SOC voltage floating around various forums, but AMD themselves raised SOC to 1.2v in their own overclocking guide just to get to 2933MT/s. I personally have to run about 1.21v to stabilize my own memory overclock.
AMD Official AM4 Tuning Guide
How can you get your fancy-out-of-spec-RAM to work fast? Well, you are going to have to set it up yourself. Luckily there are a few kits out there like FLAREX that have automatic profiles that usually work fine for AM4. Unfortunately most of the RAM on the market just has Intel X.M.P. timing charts that rarely work automatically on Ryzen because the memory controller just can't handle speeds like that without some manual help. This means you will most likely have to set ALL of your timings manually and adjust your voltages MANUALLY. This can be a real daunting task for most users to consider. Even for veteran overclockers, manually testing timings one at a time can be rather tedious. Luckily, there is a tool that can help eliminate much of the guesswork. A forum user by the name of 1usmus has been sampling various RAM kits, and has compiled a list of "SAFE" and "FAST" timings in a calculator. To make the calculator work, you'll need to figure out what memory ICs that your RAM kit uses. To do that, you can use Thaiphoon Burner.
Thaiphoon Burner
Ryzen DRAM Calculator
Ryzen Memory Guide by 1usmus
The DRAM calculator is an estimate, so if it doesn't work, try loosening timings and adding more voltage before blowing up the forums about your RAM blah, blah, blah (you'll just look like an idiot).
Read your motherboard manual and verify that you know how to manually CLEAR CMOS. This will be important to recover if you overbork your settings.
To measure the effectiveness of your memory overclock, I suggest the AIDA64 Extreme cache and memory benchmark. To test for stability I also suggest the AIDA64 Extreme stability tester. Unstable memory will corrupt your OS.
AIDA64 Extreme
And remember kids, READ YOUR MOTHERBOARD MANUAL.