I should have listened to The Pook immediately, but I had to gather some courage first
I finally tried again, now with XMP disabled. And everything worked, the machine posts quickly, without the CPU, GPU, Memory and BIOS leds blinking for a while, resulting in defaulting to 2133 Mhz (as was with XMP, even with manual timings). I would conclude that the XMP does not work in my case.
So this is how I got to 2933 Mhz:
Everything else on BIOS default except:
DRAM voltage (CH A/B) - 1.37V
XMP - disabled
Memory timing mode - Manual
System memory multiplier - 29.33
CAS Latency - 15
tRCDRD - 17
tRCDWR - 17
tRP - 17
tRAS - 36
I also tried 3200 Mhz (XMP disabled, manually setting the XMP profile timings), but in this case the Windows 10 boot failed with "Bad system config info". I had to reset to 2933 Mhz to get Windows to boot.
Any suggestion what to try, either to optimize speed for 2933 Mhz or to try 3200 Mhz?
Couple of oddities that I noticed:
1.) BIOS and HWINFO64 both report DRAM voltage 1.38V, but Ryzen Master shows the 1.37V.
2.) Actual timings achieved are 16-17-17-17-36-69-514-1T (Ryzen Master and HWINFO64), even when set in BIOS to 15-17-17-17-36. HWINF64 show 15-17-17-33-50 as supported for 1467 Mhz for these memory modules. Perhaps I will give that a go, and see it it posts.