I'm planning to use a pre-binned 9900K because my use case needs very high single / low thread performance as well as good multithread performance.
Thats why I will have to OC it as well as possible (within reasonable scale), so VRM performance indeed matters with the high 9900k power demands.
I have a very unusual use case, where one requirement resulsts in wanting to drive 3 seperate M.2 NVMEs as dedicated devices (no RAID) with very high IO counts. I would definitely prefer to put the SSDs on direct CPU attached lanes. Thats what I need the PLX chip for (9900k supports only up to 8x/4x/4x - not enough for 3 SSDs + GPU. And only very few boards support pcie bifurcation, anyway).
Only other possibility would be an AOC with pcie x8 to 4 port pciex4 NMVe M.2 with plx chip (like
https://www.supermicro.com/products/...-SHG3-4M2P.cfm). The downside of that solution would obviously be the bottleneck on the x8 pcie side. Thats why I'm considering the WS Z390 Pro, but I can't get any details about the VRM and would like to know a little more about it. I concur that the whole VRM discussion is probably a little over the top, but as it seems to be at least a little bit valid, I would like to clarify this in advance. For example, I read or watched somewhere in a mainboard comparison / review (don't remeber exactly where, would take a little time to find it again) that one of the Maximus XI Hero needed a significantly higher voltage level (of course considering different vdroops) than other boards they compared it with (e.g. Gigabyte Aorus Master) to maintain the same stable clockspeed on the same processor. That of course drove the temps even higher, VRM as well as CPU. They speculated the instability at the same (lower) voltage than on the other boards might be caused by the higher output ripple of the ASUS VRM.