I can seemingly do 6400@1.4v 1:1 with 32-38-38 with the trfc at 512 pushing vsoc to 1.2-ish but I haven't validated that very well (just about 4 hours of karhu) but touching other timings seems to result in instability or me needing to clear CMOS. I didn't push the RAM voltage any higher because it was already averaging in the low 50s and seemingly spiked up to 61 according to hwinfo when I left it overnight running karhu.
I have yet to touch nitro because I'm still very uncertain as to what it is/does, if anyone has any anything I can use to read up on this please feel free to share.
I think my goal at present is just trying to get 6000 stable at the tightest timings this kit can do since higher frequencies seem to require a fair bit of soc voltage which kind of starts eating into my cpu power budget hampering how far I can get with PBO and a negative CO offset. I'm uncertain if higher memory bandwidth would be more beneficial than raw CPU perf in this case.
On a side note, any recommendations for testing how much soc voltage I actually need? I could do 6000 with just 1.03 and it doesn't seem to error out at all with karhu and a couple tm5 profiles but I'm open to any other suggestions I can use to properly validate my overclock.