Chiplets are only a small part of the cross-CCX latency. Chips and Cheese tested the HX 370 in depth, and the 3950X has half the cross-CCX latency of the HX 370. Strix Point's cross-CCX latency is so bad, it's higher than the DRAM latency.
In comparison, the 9950X's cross-CCX latency is only...