Just another confirmation that OPs solution is legit. The Lexar 633 card is near silent, I have to crank to house shaking volumes to even make it audible
Just for laughs, I tried a normal Sandisk card too and although the access noise was there, really wasnt anywhere near as bad I was expecting.
Using a CoreGrafx, an OSSC and RGC Packapunch MD2 cable. Also tried with my SuperGrafx but thats well known to not be affected by this issue.
I saw someone beat Splatterhouse so I thought I'd have a crack