*edited for clarity, sorry*
@infrared
The only ones that make a difference are command rate, you're automatically sorted there with Ryzens, primary timings obviously and then the two following, nothing else really:
1) if you can be asked, because it takes a really long time, you should start with the IoLs, they affect round trip latency (it being something you can only affect indirectly, hence the IoLs's importance).
- Fully manual RAM settings, ie each channel's settings added separately.
- As low IoLs as the mobo allows, one channel at a time, starting with A.
- reboot, it will hang.
- clear CMOS, 'cause it may never boot again (hence my saying if you can be asked, when it hangs because of IoLs, it really... hangs).
- load last stable, again channel A, again IoLs, just one notch up.
- reboot, will probably hang
Until it doesn't. Once there, set the other channel to the same exact IoLs, reboot.
If it hangs, remove CMOS, default, load stable, increase voltage slightly* until it doesn't. Both channels must be the same, if voltage doesn't help, you need up both one notch.
*only increase voltage to match the second channel's IoLs to that of the first. As far as the first one goes, you only test to see how low it can boot with, don't mix it with voltage, this is a 'can or cannot'.
2) Then you go for tRFC, that one's just like the primary ones, increase voltage, lower it, test, rinse & repeat.
(occasionally,
slightly increasing [yes, increasing] TREFI and TREFIx9 might help in attaining stability without increasing voltage. Depends on your patience; emphasis on slightly and
never lower them).
The rest you won't even feel, not even in purely synthetic benchmarks. Only e-peening