An example of DIMM vs non-DIMM (soldered) ddr signal integrity analysis is in here: https://www.signalintegrityjournal.com/articles/1731-signal-integrity-charac

An example of DIMM vs non-DIMM (soldered) ddr signal integrity analysis is in here: https://www.signalintegrityjournal.com/articles/1731-signal-integrity-characterization-of-via-stubs-on-high-speed-ddr4-channels https://www.signalintegrityjournal.com/articles/1731-signal-... And the connectors aren't just increased resistance, but cause reflections of the wave. And surely the routing issues are self-evident? No constraints of pushing all the signals through a specific pinout edge connector. All that is (one of) the reason all gddr is soldered, and apple's M1 gets a super wide memory bus at low power by being even closer on-package.