ah, temporary possible solution: deploy spare 500W PSU to feed the second GPU power input... ugly, but it would do... and also, if this is the problem, then the memory glitch actually is not a fault but from a voltage drop
just looking up the options for a replacement and it's abysmal rn for getting a grunty PSU any time soon
i can just top the power pin and route a cable and leave the case open
if it really bugs me that much
unless there is some way to gimp the GPU so it doesn't run so fast... underclock it maybe... might be less ugly