Well, if it’s working on a 1:1 ratio and the CPU is clocking at 3.4GHz then the RAM will be running at the CPU speed, but the 5800X3D turbos up to 4.5GHz, so that isn’t a fundamental limitation. CPU base speeds are not representative of performance under load. My 13900K has a base clock speed of 3GHz but it turbos up to 5.8GHz stock (5.5GHz if across all cores) and can be overclocked to 6.1GHz with the right chip. Again, I’m no AMD expert but presumably once the CPU boosts beyond the speed of the RAM then the clock ratio changes to keep the RAM running at a speed it is capable of.
I think you might need to consult an AMD expert here 
(Edit: this is a poor explanation but I will leave it here.)