You should apply changes to both GPU VRMs. CLI works with GPU selected in the main tab of RivaTuner. There is /sd<device_index> or /selectdevice<device_index> command allowing to change device selection via CLI. <device_index> is 0-based logical display device index, i.e. if there are 4 virtual display devices (2 heads representing independent displays for the primary GPU and 2 more heads for the secondary) then your should select the first (0) then the third (2) logical devices when applying the changes. In this example, command line for probing VRMs of both GPUs can look like:
RivaTuner.exe /sd0 /ri3,70,1a /sd2 /ri3,70,1a
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