OK, thanks for clarifying again :)!
I noted that SIV (System Information Viewer) could list the two DIMMS on the same machine (Yoga 730-13IKB) so maybe they are able to use the proprietary method:
Hi,
I have been using HWiNFO since 2010 and it has been an immensely useful tool. I recently got a Lenovo Yoga 730-15IWL (81JS) laptop and just noted that HWiNFO64 seems to detect only one of the two RAM modules installed in the system. This system has 12 GB RAM installed but only the 4 GB DIMM...