Just trying to clarify as you say their usage can be avoided but I don't see an alternative mentioned. Thanks!
The alternative would be buying a different board. I don't know why you would buy a board that doesn't support what you plan to do with it. I understand risers have been solid for people in the past, but I've done fine just buying boards that have the amount of slots I plan to use. I guess I've just had the benefit of not being put in a position or situation where I am trying to make something work that wasn't meant to. If you buy a board and a bunch of cards that you didn't research, then I guess yeah you could use risers to fix your mistake. I just wouldn't suggest them as a first option or a priority.
it is kinda hard to find a board to do 8 NVidia gpus on one pc or to do 8 nvidia and 8 amd on same pc. there are some boards with 4-6 slots and one that I know of with 8 (octominer) but risers are easy and there is a semi cheap mobo that you can hook 16+ cards to.. so having 3-4 pcs to do the job of one is a massive waste of resources/money. asus b250 mining expert. you can hook 3 separate psu's up to it for whatever combo you have in mind.