@the_leander.
In relation to K7 motherboards, I have never bought anything outside of ASUS, MSI and Gigabyte brands and only limited to NVIDIA and VIA chipsets. thus I haven’t seen any scenarios that you have describe.
ECS K7SOM… a SiS740/962L chipset as I recall... My last SIS based solution was from Pentium II era e.g. BX Pro (5595) junk.