AMD Ryzen CPU Core Scaling Performance

[L_A_G]

if you increase just clock, timing don't change. but if they will still work, then they are too high for non-increased clock

If you take it too far, but most higher end memory can be made to run at significantly higher clock rates than their default clocks.

so, why does your imaginary memory vendor rates its memory with higher timings than supported?

Eh? Timings are always fixed, but clocks aren't. Vendors obviously sell different memories with different stock clocks and timings to create a range of products with higher end memory that sells in smaller volume but makes up for it with higher profit margins and lower end memory that has a lower profit margin but makes up for it with higher volume.