@eek2121 thanks
Did you watch the video? He specifically bought retail Threadripper and Epyc CPUs. He specifically pointed out that the traces appear to be the same. That Threadripper wouldn't be able to use the additional Epyc pins should be obvious, none of the SP3v2/TR4 boards would be prepared for it anyway. But IF is already able to route any memory controller and any PCIe interface through any die anyway, so Threadripper's limit to 4 channels and 64 lanes doesn't require to disable dies, it would just naturally increase latency and bandwidth saturation.
Very little is known about X399 and it's capabilities, much less the motherboards that use it. Also, X499 (or whatever AMD calls it) would undoubtedly improve things. The fact that there are 4 dies on the CPU tells me that they prepared for 32 cores (in case Intel decided to up the game), but ended up not doing it. I haven't seen any detailed shots of an X399 motherboard (other than reading tech documentation, which could EASILY leave things out), but I wouldn't be surprised if AMD worked with board manufacturers to support a possible 32 core CPU with more PCIE lanes and 8 channel RAM....at the very least for x499 (with X399 falling back to quad channel RAM, etc). Note that I don't bring this up as a subject of debate. It's just that I know the AMD of old, and I'm starting to understand Lisa Su's style. She likes to keep expectations low and over deliver. I hope her tenure at AMD lasts for a while, because she will carry them far. I also am not an AMD fanboy, but year after year of pitiful performance increases has me fed up with Intel. I wouldn't have purchased my Threadripper if it couldn't compete with Intel chips, but it does. It does so very well. IMO Ryzen Gen1 is the equivalent of the K6-2. Worst case, Zen+ will be the K6-3. If Zen+ ends up being the equivalent of the Athlon...well...Intel deserved it. In all cases, unless Intel is already taking steps to turn things around, Zen2 is going to be the equivalent of the Athlon, and Intel will once again find themselves 2nd in a 2 horse race. I hope it happens, not because I want either company to lose, but because I want Intel to stay on it's toes and remember that you can't slack off in this industry. I own Intel and AMD shares (though due to a purchasing spree last month my AMD shares now vastly outnumber the intel ones), so I have money involved on both sides. Whichever happens, I hope to god it's a win for we, the consumers.