I got a 5900X in Austria yesterday for 410€. Production code is BG 2205SUT, the CPU is a B2 stepping. I haven't tried OCing (inc. memory) yet, as I want to be sure that everything works like it's supposed to first, so a regular DDR4-3200 CL16-18-18-18-36-56-1T-GDM OFF at 300ns tRFC for my 2x16GB DR CJR it is atm. CPU-Z single core yields 665-675 points, Cinebench R20 multi is ~9730pts IIRC.
What I've noticed is that Ryzen 5000 is extremely energy efficient compared to my old 3900X. Compiling code yields me 4,45Ghz sustained all-core instead of 4,05Ghz, while having lower per-core energy consumption (10W instead of 12~13W). I do also regularily see 4.85-4.9Ghz single core boosts and my "weakest core" on CCD2 can sustain 4,575Ghz (still higher than the 4.45Ghz the 3900X could hold) in a single threaded, core pinned 7z compression benchmark. Elden Ring shows 4.65 to 4.75Ghz during gameplay.
Temps have been great so far. I haven't exceeded 70°C yet with custom liquid cooling (Phanteks Glacier C350AP). Also, there haven't been any sound, USB or PCIe issues w/ my X570 Aorus Pro r1.0 F34. I let my frequency monitor run over night to see what the boost algo does in background loads (this is on Linux without the amd-pstate driver which can increase boost further):
I think I got a pretty solid chip here. I'm curious to see what sustained clockspeeds I'll be able to achieve with curve optimizer and how far I can push my FLCK. My old 3900X could boot 2033Mhz FCLK and somewhat easily stabilize 1900Mhz.