But isn't it going to have the same old lopsided cache? I suspect we will need Zen Part 6 for a significant improvement and it will require a new mainboard with faster RAM and fewer free PCIe lanes yet.
Gamers want lopsided cache. As far as gamers are concerned, there's no other reason to have PC. Even the 5800X3D is an amazing chip for gamer needs and that thing is now two generations old. The PCIe limits aren't an issue for those gamers, either. All they want is as much GPU as they can afford anyway. It's hard enough to justify a full ATX motherboard to those people.
It doesn't sound like PBO is making a huge difference for anything Zen 5 right now but the difference between Linux and Windows performance gains IS quite puzzling. Some analysis says that AMD didn't make any changes from Zen 4 to Zen 5 in its memory controller and others suggest that Windows is seeing doubled latencies between the CCXes on Zen 5 vs Zen 4, so there are clearly places where some part of the architecture has fallen down.
I'm reading everything I can find because I want to justify the CPU switch from the 7600x to the 9950x for my presumptive new desktop, which means I AM following along with Twitter and Reddit nonsense right now but I have compatible hardware and it's not going to kill me to not spend $600whatever until there's some sign of improvement.
AMD does have a habit of releasing refined products after a while. I can't imagine that they were rushing to ship something new, but I do kind of wonder why they put something out knowing full well that it would be AMD's version of the fourth generation that Intel released a 14nm-based CPU.