Setup:
Ryzen 9 9950x
Asrock b850 pro-a
4 x Kingston 64gb 5600cl36 sticks(Samsung chips)
Arctic liquid freezer 3 pro
Not as cool as some screenshots of 5600-6000Mhz 256gb setups on msi boards i have seen but it will do.
Passed: 28 hours of testmem5 absolutnew,
15 hours of y-cruncher vt3.
No matter what i changed i couldn't go over 4800Mhz. Even 5000 wouldn't boot at all.
4800Mhz though booted straight away, no need for any additional tinkering.
Temps: 2 middle sticks got up to 62-63c, 2 others – 57-58c(fairly conservative fan settings in well ventilated case). No additional cooling was provided, but vrm fan of lf3 pro lowered temps by 2-3C.
As for cpu, i only set limits in pbo to motherboard, no undervolting at all. Seems like this chip is well above average. It hits 270w in cb r23.